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One cat is great, so more cats are obviously better, right? Even if you have generally very sweet, friendly cats toward you or other cats, you need to do a careful introduction. Cats are extremely territorial so cat introductions can be tough. A new cat in their space that they are not familiar with can make even sweet cats become not so sweet.
This is a comprehensive guide to give you the basic steps to help you give your cats the best chance of living in harmony (or at least tolerating each other). If you want more specific advice, I’m happy to set up a consultation to help you figure out how to introduce your cats.
Before The New Cat Arrives
Setting up your space ahead of time will prevent a lot of problems later. In order to get your new cat adjusted to their new home, you’ll need to give them their own separate space. Usually this will be a separate room, but work with the space you have. If you can give them their own floor or wing of the house, even better.

This space should be quiet, a comfortable temperature, and somewhere any resident cats don’t need access to. It shouldn’t have any dangerous objects, including plants you don’t want the cat munching on or anything that could injure the new cat, and ideally should be a location you are comfortable spending time in.
Things To Get
Set up the space to make sure all your cat’s basic needs are met in the room. These needs include:
- An appropriate litter box
- Food and water/a water fountain (placed separately from the litter box)
- Scratching post
- Bedding
- A hiding place or places
- Toys
- Somewhere to climb
Begin familiarizing yourself with cat body language. It will be extremely important later in the introduction process to be able to read what each cat is telling you about their comfort level. I suggest Lili Chin’s excellent guide Kitty Language for an easy-to-follow resource on how to read cats.
Introduce By Scent
If possible, obtain something that smells like your new cat ahead such as a cat bed they snuggled into frequently to allow your cat to get used to the new cat’s scent. If you can leave something that smells like your cats (bedding or a towel works great) with the new cat, it will help them become familiar with your cats’ scent.
Make Environmental Changes
A few days (or longer if your cats will be particularly distressed by closed doors) ahead of bringing the new cat home, close the door to the room so your resident cats are used to not having access to it. Use this time to make any changes you need to the main living space so that all cats have their basic needs met spread out in different locations.
You need at least one of each resource for each cat, though adding an extra is always a good idea. This is particularly true for litter boxes! A good rule of thumb is one litter box per cat plus one extra and at least one on each floor of the house. The litter boxes especially should be spread out and not all put in one location.

Bringing The New Cat Home
Bring your new cat home in their carrier and directly to their safe room. Do not try to carry the cat in without a carrier, let the cats see each other, or introduce the cat to the other cats in the carrier. This is extremely scary for the new cat and I strongly advise against using carriers to introduce cats. Covering the carrier will help the new cat not see any other cats as you transport them. You can also temporarily distract the resident cats with a food puzzle or keep them in a separate room.
Set the new cat’s carrier down in their room and allow them to decide if they want to get out or not. Never force a cat out of hiding as this will just make them more fearful. Let them explore their new space as they feel comfortable. No need to do anything like showing your cat their box.
They may run and hide or they may hiss at you. That’s okay! Let them settle in.

Exploring And Meeting You
Leave the cat alone in the room for a while to settle in and explore. You can go in to give them food and check they have plenty of water if needed. Eventually, you can go in and sit quietly in the room, preferably on the floor or at the cat’s level. Let the cat come to you and initiate contact. You can offer a finger, but present it at a distance without shoving it in the cat’s face. The cat may sniff you, but be cautious about petting them right away. Start out petting only their chin and cheeks at first for a brief moment if the cat lets you.
Spend time in the room with the cat. As they seem more confident, you can begin playing with them and interacting more and more.
Preparing For The Cats To Meet
While you let the new cat settle in, you can swap out bedding from the other cats so the resident cats and the new cat can get used to each other’s smells. Observe the cats’ reactions and do NOT move forward with the introduction if there are any negative reactions to the smell as it could signal a problem with the introduction.
You can also take the lazy but still effective approach by wearing the same clothing as you switch spaces and letting each cat rub against you. This leaves a bit of their smell on you and serves essentially the same purpose as swapping bedding.

Skip Feeding On Opposite Sides Of The Door
You may have heard the suggestion to have your cats eat on opposite sides of the door that separates them or a pet gate during the introduction process. This advice is an out dated method as cats don’t naturally eat in groups. Most of the time, they’re catching small prey that isn’t easily shared so eating near each other is aversive.
Another problem? Cats will eat near each other unless extremely stressed. That doesn’t mean they like each other or will be fine meeting face to face. Eating is a basic need for survival so they may put up with being near a cat they aren’t comfortable with in order to eat. Food is very motivating.
Better Options
Play or positive reinforcement based training are better choices. One of the most important things you are trying to teach the cats is what to do when the other cat is around. You aren’t teaching them what to do by only setting out food or tossing treats at them. By playing or training your cat, you’re directly teaching helping the cat learn options of what to do and building a positive association.

When To Move On
Every cat is different and every pair of cats is very different. A confident cat may need less time in the safe room and a more timid cat may require longer. For the whole introduction process, you have to go at the speed of the cats (even if you would like to go faster).
This means listening to each cat individually if you have multiple cats to introduce. Don’t rush the process or you’ll have a group of very stressed out cats.
Location Swapping
Once the cats are completely calm at baseline, temporarily heard the resident cat(s) into a separate room and allow your new cat out to explore the main living space room by room on their own. It’s less stressful to introduce a cat to a large space room by room. This helps the new cat get used to their new home and builds a colony scent.
Ideally, you’d have a separate safe room for your resident cats to go into while the newcomer explores the more neutral middle ground. If you can’t do this, you can swap your resident cats into the newcomer’s safe space without the cats seeing each other at all. If this isn’t possible, it’s best to just skip this step entirely.
Keep The Play Coming
Continue to have the cats play with a toy under the door with the door still closed between location swaps. If you want a creative way to do this, use a ball track for mutual play. You can also work on clicker training with your cats. I’m available for lessons on clicker training or you can get a clicker training kit to try on your own.
Introducing Cats Visually
Once everyone seems calm you can start letting them see each other very briefly with a barrier between them. There are many to accomplish this: full-door length pet gates, extra tall gates, or you can use two regular baby gates. If you have the time and patience, you can consider making your own gate.
I strongly recommend going for a full door length gate because just because your cat isn’t a leaper normally doesn’t mean that won’t change. Go for one of the gates that is at least 70 inches high if possible.

Brief Meetings
For the next part, you will have the cats repeatedly see each other for short periods of time with the barrier between them while the cats are doing something. The goal is to make this a positive or neutral experience for the cats so they don’t become frightened. Over time, you can gradually increase the amount of time these meetings last.
One of the biggest mistakes people make during this part? The benefit doesn’t come from the cats only seeing each other; they need to not become fearful of each other. Make sure the cats have something to do when they’re seeing each other instead of just throwing the cat up and leaving them be.
Details Matter
For this phase, you’ll end up as a client of mine if you’re not careful. I’m awesome and love helping people with their cats, but needing professional help introducing cats is not something most people want to do. Pay very close attention to the following:
- Distance between the cats: Keeping the cats as far apart as possible to start will be less stressful for the cats. Only let them get close to each other gradually.
- Keep the cats busy: Your cats should always have something to do such as clicker training, a pattern game, or playing when they have visual access to each other to start. Removing things to do so they can figure out how to be around each other comes much later.
- Treats can be given after a meeting: The key here is after a visual meeting (unless you’re doing clicker training). Ideally, give the treats away from the door or where the cats may see each other.
- Keep meetings brief: It’s best to start out having the cats see each other for only a few seconds to gauge how they do.
- Stop if there is hissing, growling, staring, or any concerning body language: Your goal is to end the meeting before this occurs, but if it does, you need to call it off right away. The more negative interactions the cats have, the higher the risk their relationship will deteriorate. Contrary to popular belief, it’s not normal for cats to get in fights when they meet. You want to avoid this.
A Note On Hissing
It’s not necessarily abnormal to have some cat hissing at first so a few hisses doesn’t mean that things are hopeless. It should lessen over time, but it’s still a good idea to end the interaction early in the beginning so things don’t progress to a full cat fight. Eventually, some hissing can be okay, but you don’t want to risk it in the beginning.

At this point, you may want some help if the cats are not digging each other as it’s easier to prevent a negative association than it is to fix an introduction gone wrong.
Removing The Gate
When the cats are do not react to each other the gate for a significant amount of time (the longer the better, but you should always be supervising them at this point), you can have them meet without the gate for the first time. Always have a towel, flattened cardboard box, broom, or cushion nearby to gently separate the cats if needed.
A Word On Harnesses
Harnesses and carriers are sometimes recommended for this phase, but you should skip them. While harnesses can have their place in some circumstances, you absolutely have to condition the cats to enjoy being in the harness. They are only be there as emergency backup because they don’t teach the cats what to do or help them with their emotions. Unless you plan to have your cats harnessed constantly, they’re not worth the effort.
Active Participation
Rather than just removing the gate or opening the door to let your cats out, take a more gradual approach. This is where full door length pet gates come in extra handy!
- Keep your cats distracted and really far apart at first. Have someone else open the gate very briefly and close it.
- Move the cats closer as they demonstrate with the behavior that they can handle the gate being open without bolting. Play is your best option for this part. I used two Cat Dancers when I was introducing Poutine and ‘Zac.
- Have one cat play their way through the door or open gate then back right away.
- Continue doing this until the cats are fully in the same room as each other but still far apart.
- Gradually increase the amount of time the cats are together with distraction and then gradually remove the structure and distraction.
You should continue to end sessions before the cats show signs of anxiety or stress. You’ll know the cats are ready to have more time with each other by how boring this process is. It shouldn’t be that exciting.

When To End Active Participation
As you feel comfortable, you can begin letting the cats have unstructured time together and eventually short unsupervised time together. Add this in only if there hasn’t been staring, growling, or hissing and the cats are ignoring each other. Your goal isn’t necessarily cats that want to be around each other constantly; it’s cats that don’t try to maul each other.
Do I Have To Do This?
I mean, no, I’m not forcing you to. But…
This all seems like a lot of work and I won’t deny that it can be depending on your particular cats. Some cats may take a few days to adjust, but you should go into this expecting it to take significantly longer. It’s not abnormal for a cat introduction to take a few months. It also doesn’t need to involve a lot of hissing or stress for your cats.

In the end, introducing cats correctly is less work than trying to fix a cat introduction gone wrong. This process is way easier to do than a reintroduction! And seriously, if it seems like a lot of work, I’m happy to help you out.
I hope your new cat, resident cats, and all humans involved enjoy their new home together and you all have many years of happiness ahead!