Greetings feline friends! Skye Blake here with a step-by-step guide to introducing a new cat to your resident cats.
Before bringing a new kitty home and creating a disaster, discover how to prepare for the big day.
Don’t skip this because preparation is key to a successful feline introduction… “How Do You Do? Introducing Cats“.
The information here is for general knowledge… always see your vet with questions about your cat’s individual needs.
- Who Is Skye Blake?
- Introducing a New Cat – Step-by-Step
- Step 1 – Bringing the New Cat Home
- Moving Forward
- Step 2 – The Sock Swap
- Step 3 – The Room Swap
- Step 4 – Love at First Sight
- Step 5 – Finally Opening the Door
- Reintroductions – Similar But Different
- List of Sources
Who Is Skye Blake?
Skye Blake, Cat Info Detective, is a curious cat researcher (not a veterinarian or behaviorist) who sniffs out expert, reliable sources about cats, studies their information, then passes it on to you!
Sometimes there’s not enough evidence for easy answers, so Skye gives you all sides, explains the situation as thoroughly and clearly as possible, and links you to experts on each page.
All sources are at the bottom of each page so you can do more snooping…
Introducing a New Cat – Step-by-Step
There are five basic steps to introducing cats to each other.
They’re simple but require you to be in charge and aware of how each cat is reacting.
The difficulty comes in when people get impatient and try to rush the process.
It has to happen at the pace of all cats involved… not the human’s!
Some people try to put the cats nose-to-nose, thinking that this will help speed the process.
Huge mistake… it won’t end well and all of you risk injury… again, don’t force it!
The process of introducing them can take anywhere from a few weeks to months depending on each individual cat.
According to cat behaviorist Pam Johnson-Bennett…
“There are two important aspects to the introduction process that I want you to remember.
The first is that the process must be done one sense at a time, and the other is that you must give the cats a reason to like each other.”“Cat vs. Cat” by Pam Johnson-Bennett, Certified Animal Behavior Consultant, Penguin Books, Penguin Group (USA) Inc, New York, NY, 2004, p. 51
Step 1 – Bringing the New Cat Home
The big day has arrived!
Make sure the door to the room is closed and no other cats are in there with you.
Open the carrier door and leave it open. Leave the room and let her come out when she’s ready.
An adult cat may or may not come right out… depending on how wary or confident she is.
If it’s a kitten, stay long enough to show her the litter box, beds, food and water bowls.
Keep a robe or change of clothing in the room.
When you hold or pet the new cat, her scent won’t go with you to the other cats.
Wash your hands afterward before being around your other cats.
This is important… the strong scent of unknown cats can overwhelm and threaten any cat, even if it’s on you.
Some scent will still be there even after washing and changing clothes, but it will be milder and not threatening.
This is only necessary at the beginning while they’re all learning to associate each other’s scents with good things.
Play is very important both while introducing cats and afterward,.
It’s necessary physically, mentally, and to satisfy their hunting instincts.
You should already be playing daily with your cats, but if not, this is a great time to start.
Wand toys are a great tool for distracting and guiding them, as well as providing fun, draining energy, and building trust.
Spending 20 minutes or so playing quietly with the new cat builds trust between you since he now associates you with something good… play.
This is also true when you feed her… another good reason to end with a meal or treat at the end of playtime.
If you brought home a kitten, playing helps drain all that rambunctious kitten energy.
Playing with resident cats during this time is important for the same reasons, as well as establishing or continuing a comfortable routine.
Once the new cat has arrived, the other cats will smell him and be curious.
They’ll start sniffing at the door, even sticking their paws underneath it.
This curiosity is normal and a good start to the final sight introductions that you’ll eventually do.
But don’t let the new cat rush up and get too close or touch their paws.
The closer he gets, the stronger all their scents become, which can quickly become threatening.
Remember, you want to build positive associations for all the cats, not negative ones.
Either redirect the new cat or the resident cats with a wand toy before any distress starts.
Having somebody on each side of the door makes it easier to control their meet and greet time with redirection.
Using a toy or treat to redirect their attention prevents problems but also creates a positive association with each other… that’s a win-win!
The cats start to realize… “hey, this new scent comes with fun and treats”!
This is the key to successfully introducing cats.
Making Sense of Scents
By introducing your cats one scent at a time, you’re keeping them from being overwhelmed and going on high alert.
Sight is the most threatening sense for cats because most intimidation and challenge for territory takes place with eye contact… especially “the stare”.
Once cats are introduced and accept the new cat’s scent, sight is less threatening.
How do you know when it’s ok to move to Step 2?
Since you know your cats best… when they’re upset and when they’re calm and happy, you’ll be able to tell when they’re ok with the mysterious cat behind THE DOOR.
Use your best judgment but don’t rush it! That’s the biggest mistake people make.
Resident cats should be in their normal routine, sleeping, eating and playing, curious about the safe room, but not upset.
They shouldn’t be redirecting their stress onto another cat (or you) when they smell the new cat.
The new cat should be secure and comfortable, even curious about who’s on the other side of the door… not hiding.
Step 2 – The Sock Swap
The sock swap is a great way to introduce stronger scents to every cat involved.
It’s safe and non-threatening… and you can control the situation.
Why a sock? Because anything bigger, like a towel, can be too much scent and make a cat feel threatened.
Scenting the Socks
Use a pair of socks that don’t have any strong scents like detergent or fabric softener.
Use one sock for each cat… don’t mingle cats’ scents on one sock so the new cat doesn’t get overwhelmed and feel threatened.
Start with the calmest, most accepting cat and gently rub his cheek to get facial pheromones on the sock.
Don’t rub anywhere else on the cat’s body because other areas contain pheromones that that signal other emotions… some are even warnings.
Using the only facial pheromones signals calm and happiness, which are welcoming to a new cat.
Then take a new sock into the safe room and rub it on the new cat’s face… but only if she’s ok with it.
Don’t force it… if she doesn’t want it or is afraid, just put a couple new socks in her bed.
Then after she’s slept on them, you’ll at least have her scent.
Leave the resident cat’s sock in the safe room and put the new cat’s sock on the floor where the other cats live.
You’ll be able to see how your cats react to the newbie by how they react to the scent sock.
In a multiple cat household, some cats might sniff and walk away (yay!), while others might hiss, growl, and even attack the sock (oh dear!).
Sniffing and walking away is great that cat is signally the new cat’s scent isn’t a threat and is allowed in his territory (but don’t open that door yet!).
Negative reactions show a cat feels threatened and will need more time to accept the scent owner.
Don’t be discouraged about that… it only means you have to give that cat extra time and work on more positive associations.
This is a common reaction, which is why using the sock swap method is so good.
You can determine all your cats’ reactions while keeping everyone safe and can redirect a negative reaction with play.
If you play and end with a treat near that sock (bringing the toy closer a little at a time), this will change the negative reaction to a positive one.
Repeat the sock swap a few times a day until everyone’s sniffing and walking away.
Once you’ve accomplished this you can swap other things that have a stronger scent, like beds, toys, blankets, and trees… monitoring reactions closely.
Having your cats eat near each other without being upset about the other cat’s presence is a big deal.
This must start while they can’t see each other… it’s actually simple but requires you to monitor their reactions.
This is easiest when you have a helper on the other side of the door watching the new cat while you watch the others.
Put each cat’s bowl down at the same time at a distance from the safe room’s closed door.
The scent of the other cat will upset them if they’re too close together, so most people start across the room (at least six feet away on both sides).
The distance at which both cats start is where they’re able to walk to the dish, eat, and walk away calmly.
Mark the starting lines using masking or painter’s tape.
They should have no signs of stress, like looking around cautiously, tail flicks, creeping, running up to the door and swiping, hissing, or spitting.
Don’t let this happen or at least stop it the instant it starts.
Move the bowl back for that cat until he’s relaxed and able to eat comfortably.
This is important because you must end each session with a positive association… “oh, ok, I get to eat while smelling this new cat… and nothing bad happened.”
Move & Repeat
Each time you present a meal, repeat this routine, moving the bowls toward the door a few inches at a time.
But only after there have been 2-3 meals where there’s no negative reaction.
Don’t rush it or you’ll have to start over!
You may have to keep it at one spot for every meal for a while before moving forward.
It all depends on how quickly the cats catch on and decide this is good.
The idea is to have both cats happily eating about one foot from both sides of the door.
This is the point at which you can try having them eat while seeing each other.
Eating calmly and walking away, ignoring another cat’s scent, is the success you want!
Step 3 – The Room Swap
Once all feline parties are stress-free with the sock swap, then you can start the room swap.
Swapping rooms should start with every other day to keep any one cat from over owning territory.
It also helps, along with play, to use all the cats’ energy and reduce any zoomies or other behavior that isn’t settled and calm.
Start with allowing them to switch for a few hours without a set swap time.
An example is switching them in the morning and switching back at noon.
This is important because the new cat needs to have ownership of everywhere the other cats already own.
And the other cats need to own the safe room again where the new cat has been.
It gives them the chance to leave their scents in important scent items like litter boxes and beds.
Group scent swapping is very important to keeping the peace in any cat clowder (a colony of cats).
Here are some helpful thoughts from cat behavior expert, Jackson Galaxy…
“When it comes to site swapping, there are no hard and fast rules about when and how often, as long as you are consistent.
You don’t want to swap randomly, and you don’t want to allow anyone to get too comfortable in one space.
You can swap once a day, every other day, or even two or three times a day if the cats are happy.
Just don’t let yourself fall into a rut.”“Total Cat Mojo“, by Jackson Galaxy with Mikel Delgado, PhD, Tarcher Perigree, Penguin Random House, LLC, penguinrandomhouse.com, New York, NY, 2017, p. 173
Swapping rooms is the same idea as swapping socks, just on a larger scale.
You’ll know your new cat is ready when he’s completely comfortable in the room.
He’ll be sitting in the window watching birds, not jumping, running or hiding when the door is opened.
He may even be starting to sit by the door and zip out or meow and scratch the door to come out.
Move the resident cats to another room and close the door, then open the safe room door and let him come out on his own.
Don’t pick him up and plop him in another room… he won’t know where his safe room is if he gets scared and needs it.
You can help him relax, if necessary, by coaxing him with the wand toy or treats.
Let him explore to his heart’s content… rubbing against furniture, walls, corners, and even roll around on rugs.
The Group Scent
All this is good because he’s mingling his scent with the other cats’ scents, and this will help them accept him more.
Once he’s had some time to wander around, sniff, and mingle scents, put him in a different room with a door you can close.
Then leave the door to the safe room open and let the other cats wander in to check it out (in their own time, of course).
You don’t want one cat to redirect a negative reaction to the new cat’s strong scent onto another cat by hissing or swatting.
Those you think might be more stressed by it should stay in a separate area until the others are done.
Then let the more sensitive cats go in one at a time, watching their reactions carefully, and redirecting with the wand toy or treats if they start to react negatively.
They’re already familiar with the new kitty’s scent but this is the first time being where it’s strongest.
If you’re in a small apartment and don’t have the space to do a swap, enlist a neighbor or friend to help.
They can take the new cat (in her carrier) out for a little while so the other cats can explore her room.
If any cat starts to get upset, direct them out of the safe room to where they’re more comfortable.
The most important part of room swapping is that the new cat gets to explore and scent mark the main living area of all the cats.
The other cats will get to the safe space in their own time, and they are already comfortable in their main areas.
Step 4 – Love at First Sight
Once everyone’s doing well with the new cat’s scent, it’s time to introduce them by sight.
They’ve been introduced and now are comfortable with each other by scent and hearing.
Now you can swing open the safe room door and they’ll greet each other like long lost brothers, right?
Heck to the NO!
It’s now even more important to continue the slow but steady progress or you’ll have to start over!
Since you’re adding sight to the list of senses you’re working on, you’re almost there…
But even though they can see each other now, you don’t want them to touch each other.
Here’s where it’s most important to give all the cats a reason to like each other… positive association.
There are two options for allowing sight but not touch…
- Put a up screen door or pet gate
- Open the door slightly
Screen Doors & Pet Gates
Screen doors work well because the cats can see but not touch, you can see both sides, and you can go in and out easily.
They give you the most amount of control, are inexpensive, and easy to install, even in an apartment.
You can remove it later and put the regular door back in the same place.
Pet gates are high but can’t completely cover the doorway, so if you have a jumper, it won’t stop her from getting to the other cat.
These gates also have a “door” in them so you can get in and out easily.
Slightly Open Door
If you want to try keeping the door ajar a bit, use a door stop on both sides to keep it from swinging wider.
A hook-and-eye latch will also allow you to control the door.
Have it open just enough so that if the cats start swatting at each other through the opening, they can’t hurt each other.
There’s a drawback with this method that makes behaviorists prefer the screen door.
When a door is slightly ajar, there’s still an element of hunting that can cause problems because the cats will go into hunting mode, sniff and bat paws, thinking the cat on the other side is prey.
Even though it might be play hunting, you don’t want to encourage this behavior during introductions.
It often fails miserably because the cats are nose-to-nose way too soon.
It’s better to have the screen because the cats can see the other one’s full body posturing and read the situation better.
If either cat hisses or growls, you’ve either moved forward too quickly or allowed the session to last too long.
Add a Curtain
Whatever setup you use, attach a blanket to cover it up enough so they still can’t see each other.
You can use a very large piece of cardboard to do this as well.
This gives you control over the visual introduction process so you can quickly drop the blanket when a cat begins to be stressed.
Don’t skip this step!
It’s a critical buffer that helps cats gain enough confidence to move forward with accepting the other cats.
It may seem like a lot of effort, but don’t quit now… you’re almost there!
Lifting the Curtain
Start by lifting the blanket slightly for 30 seconds at a time.
Watch the cats closely for any sign of stress, especially crouching, hissing, or staring.
Moving the blanket an inch at time allows you to keep things positive, quickly shutting down any threat before it goes too far.
If one cat runs up to the barrier, even in a friendly manner, the second cat might get spooked.
Work with the blanket while both cats are eating.
They’re already used to each other’s scent and this pleasant distraction makes it an even more pleasant association.
The goal is to have each cat comfortably eating near the other (not from the same bowl).
You can also try lifting the blanket when they’re not eating, using play as the fun association and wand toys to distract them if one starts focusing on the other cat.
Use a food puzzle or bowl that makes them slow down for any cat who gobbles the food down too quickly.
As you see the cats relaxing and accepting each other with the blanket slightly up, slowly bring the blanket higher a bit at a time.
Judge it according to your cats’ reactions, which you should be quite familiar with now.
This process of sight introductions can take days or weeks… depending on the cats.
Again, take it at their speed, not yours!
If, after a few weeks of moving slowly forward, the cats aren’t making any progress, contact a qualified cat behaviorist for guidance.
A behaviorist can help you determine if there’s something you missed or need to do differently.
It could be a situation where a cat needs drug therapy to help him calm down or might even need to be in a one-cat home.
An expert’s evaluation can make all the difference and is well worth the money.
If you have more than one resident cat, do the introduction process separately with each one.
Introducing all the cats at once will overwhelm the new cat.
The resident cats might also get upset, redirecting their aggression onto each other because they can’t get to the new cat.
If this happens, you’ll have to use play and treats to get them back to liking each other before attempting to continue introducing the new cat.
This can take days or even weeks, depending on how upset the cats are… so be patient.
Step 5 – Finally Opening the Door
Once the cats are comfortably able to see each other and eat within a foot of the door, you’re ready to begin opening the door completely.
Do this introduction a bit at a time, just as with the other steps, using distractions like toys or treats, supervising the entire time.
Since you’ve done the preparation of your home, it should be easy for the new cat to get to his safe room or get off the floor without being attacked.
Don’t change anything in the safe room and keep it open.
You’ll want to guide the new cat back into it at night or during times when you can’t supervise.
Casually supervise while your new cat is out until they’re able to sniff and walk away or remain calm for at least an hour at a time.
Having a casual “everything’s normal” attitude is vital for your cats to remain calm.
It helps them know that nothing threatening or startling is happening with this new cat around.
Have wand toys handy in each room so you can quickly grab them when you need to redirect somebody.
By now you’ll be able to read each cat’s subtle signals and defuse problems before they start.
Into the Future
Celebrate when the new kitty is in the same room as the other cats… and everybody’s calmly sharing the space.
If they start rubbing up against each other that’s great!
Rubbing is one of the most significant cat-to-cat communications.
It signifies trust so they’re marking each other as friends… this is a high compliment in the cat world.
Now the introductions are complete but just like people, cats can have problems and spats.
Keep supervising and if you have any concerns, redirect and keep making positive associations with each other.
Separate potential troublemakers when you can’t be there (remember the safe room?).
Continue the daily play and feeding rituals you’ve established… they’re the key to future long-term success!
If It’s Not Going Well
Sometimes you’re trying to make progress, but the cats are just not doing well together.
Take a deep breath, think about what steps you were able to complete successfully, and start over.
It can be discouraging but is the best way to make forward progress.
Go back to where each cat is relaxed.
Usually this involves shutting the door and working on scent acceptance again before sight introductions.
If you have to start at the beginning, that’s ok… give them extra time with each step before moving on.
It’s always up to the cats to set the pace of progress.
If you’re at your wits end or just feel you need more guidance, talk to a certified cat behaviorist about the situation.
There are a few things to keep in mind when introducing kittens to other kittens and adult cats.
Kittens are usually flexible and adapt easily to new surroundings, people and other pets.
But they do have individual personalities, and some are more sensitive than others.
The environment they came from and their socialization to people and other animals will affect how quickly they respond.
Make sure you have time to be with the kitten the day you bring him home.
This will help him settle in and not be lonely.
Weekends are a good time for most people since they can be home from work.
Help him find the litter box, bed, and food/water bowls in the safe space.
Kittens are naturally playful and energetic, which can be annoying to adult cats, especially seniors.
The process of introducing them helps older cats get used to kittens without being overwhelmed by all that wild energy.
Use the same introduction methods we discussed above, taking it at the pace of all cats involved.
Don’t rush it!
Reintroductions – Similar But Different
You can use the same steps to resolve problems between resident cats as well as introducing a new cat.
There are a few differences… mostly notably that the resident cats have already established a pattern of hating each other.
This can affect the time it will take to change their negative association with each other to a positive one.
The good news is that most cats will be able to live harmoniously once you’ve done the reintroduction… at their pace.
Having their scents mingled together on objects and each other is very important so cats can see each other as friends instead of enemies.
Even though cats are living together, you can’t assume their scents are co-mingled on each other.
Their scents are on objects they lie on or rub against, but not on each other since they don’t go near each other.
Rubbing against each other signifies acceptance and trust… so enemy cats don’t do that.
If they physically fight, they’re touching each other but the pheromones that are released are related to territorial warnings and danger.
Just using calming pheromone spray isn’t enough to fix the problem, especially if your cats are fighting.
This is important to know so you don’t skip the “sock swap” step of exchanging facial pheromones.
When All Else Fails
If you’ve tried every introduction step and the cats simply can’t get along, you may have one cat who just cannot live with other cats.
In that case, it might be best to find a one-cat home for that cat.
Discuss the situation with a qualified cat behaviorist.
If you didn’t have the cats examined by a vet, take care of that now.
Since medical problems can cause aggressive behavior no amount of effort to reintroduce them will work until those are resolved.
Here are some videos that will help you understand the introduction steps and why they work…
This video goes into more depth about how you introduce cats to each other…
Sources used on this website are either primary or secondary.
Primary sources are always preferable and have the most reliable information because they’re original and directly referenced.
Scientific abstracts and data are good examples of primary sources.
Secondary sources are weaker because they usually consist of opinions or articles that give no sources of their own.
However, sometimes they refer to primary sources.
When I use secondary sources, most are those with some authority, such as veterinarian or cat behaviorist books and articles.
List of Sources
“Animal House”, Chapter 10, Cat Wise by Pam Johnson-Bennett, Penguin Books, Penguin Random House LLC, New York, pp. 162-172
“Living with Multiple Cats” by Leticia Mattos De Souza Santas, DVM, MS, PhD, DACVB, Decoding Your Cat, by Editors, American College of Veterinary Behaviorists, Houghton Mifflin Harcourt Publishing Co., New York, hmhco.com, pp. 93-114
“Cat Etiquette: The Art of Introducing, or Reintroducing, Cats to Each Other”, Chapter 4, The Cat Whisperer by Mieshelle Nagelschneider, Bantam Books, The Random House Publishing Group, New York NY, 2013, www.bantamdell.com, pp. 125-170
“Cat vs. Cat” by Pam Johnson-Bennett, Certified Animal Behavior Consultant, Penguin Books, Penguin Group (USA) Inc, New York, NY, 2004, pp. 43-71
“The Trainable Cat” by John Bradshaw and Dr. Sarah Ellis, Basic Books, Hachette Group, New York, 2016, pp. 115-160
“Think Like a Cat, How to Raise a Well-Adjusted Cat – Not a Sour Puss” by Pam Johnson-Bennett, Certified Animal Behavior Consultant, Penguin Books, Penguin Group (USA) Inc, New York, NY, 2000, 2011, pp. 216-236
“New Kit on the Block”, Tiny But Mighty by Hannah Shaw, Plume, Penguin Random House LLC, New York, 2019, pp. 257-8
“What Are Cat Pheromones And Do They Really Work?” by Dr. Lizzie Youens BSC (HONS) BVSC MRCVS, August 5, 2022
Updated December 28, 2023