Introducing Cats to Cats & Cats to Kittens: A Complete Guide

Introducing new cats takes a lot of time and patience, but with these step-by-step instructions, you can set everyone up for a successful introduction.

Updated January 24, 2024
Two cats sitting on an orange couch

Adding a new cat to your household is a very exciting time, but you'll need to be a little patient. Rushing the introduction process can lead to behavior problems with your new and resident cat. Cats need time to acclimate to each other and learn to tolerate (and hopefully grow to enjoy!) each other's company. Success lies in laying the foundation for their relationship before you bring your new cat home and taking your time to work at their comfort level.

Matching Your Cats' Needs & Energy

Before you bring a new cat home, it's best to consider what kind of cat might do best with your resident kitty.

Adult Cat vs. Kitten

Many adult cats will accept a kitten of the opposite gender a little more easily than another adult. However, introducing a small kitten to an adult cat will require extra careful monitoring to keep the little one safe at the beginning due to the size difference. Make sure both have escape routes when graduating to the face-to-face introduction step, and never rush to push your cats to this point. 

Lazy vs. Playful Cats

Personality can have an impact, too. Katenna Jones, Associate Certified Applied Animal Behaviorist, notes that, "A rambunctious and playful senior cat would do better with a rambunctious and playful kitten than a lazy cat of the same age." 

Unspayed/Unneutered Cats

Never introduce an unneutered male cat and an unspayed female cat, no matter their age, because you could easily end up with an unplanned pregnancy. 

6 Tips to Make Cat Introductions Better

Once you've selected your new cat or kitten, it's important to keep a few things in mind before you even start the process. The tips below should be used from the moment your cat comes home and through to after they're fully introduced to help your cats get along as well as possible. Cats are sensitive to change, especially when that change involves meeting new cats. 

1. Use Scent

Cats interact with the world and learn about their environment through their highly developed sense of smell. Providing your cat with items that smell like the other cat before they meet can be a way of "introducing" them without the stress of a face-to-face meeting.

Use scent by placing a towel in the bed of each cat or rubbing it against them so it picks up their scent, then place that towel in the other cat's bedding. You can do this with toys as well.

2. Use Enrichment

Cats can become very stressed when meeting strange cats, so providing them with lots of mental and physical enrichment can help to ease their anxiety. This type of enrichment depends on your cat and their personality. It can be more window perches to view birds and squirrels, different types of cat toys, a new deluxe scratching post, or breakfast or dinner in foraging toys. Clicker training them to do different behaviors and tricks is also an excellent mental enrichment activity.

Related: 15+ Cat Enrichment Ideas to Make Their Days More Exciting

3. Use Vertical Space

Cat Sitting By Window At Home

Make sure there's plenty of vertical space that all the cats can access, as cats enjoy climbing. Having a variety of cat trees and shelves for the cats can give them more places to retreat to when they don't want to interact, and this reduces the chance of fighting.

Quick Tip

Being high up and having a bird's eye view of the room can make cats feel safer when they're nervous.

4. Use Positive Reinforcement

You always want to reinforce any behavior that you want and direct the cats away from behaviors that you don't. You can positively reinforce the cats using whatever each one really enjoys, which can be brushing, kitty treats, playing with a toy, or "happy talk" and cuddling.

Never use any type of punishment, such as yelling if the cats start to hiss at each other or spray bottles, as this can make the problem worse. If the cats are already stressed at meeting each other, throwing in punishment will convince them that their negative feelings about the other cat are justified.

5. Go at Your Cats' Pace

Be prepared for your introduction process to take quite some time. This could be a few days, a few weeks, or potentially more. Never rush the process, and go at the pace at which all of the cats involved are comfortable. Too much too soon can be counterproductive and increase stress levels, which can lead to fighting.

6. Read Their Body Language

Learn all that you can about cat body language so you can stop sessions from becoming too much for the cats. If you're familiar with their signs of stress, you can notice when one or more cats is feeling anxious, threatened, or aggressive and remove them from the situation before those behaviors escalate.

Quick Tip

With a little bit of knowledge about cat behavior, there are a few ways that you can make introductions go smoother.

How to Introduce Cats: Step-by-Step

Follow each step below, and do not move on to the next step until both of your cats are calm and relaxed for each part of the process. Always remember to move at the pace of your cats, which means all of them must be relaxed before you proceed.

1. Keep Them Separated

You'll need to keep the cats physically separated in the beginning. You can accomplish this by keeping your cats in separate rooms behind a closed door. You will want to rotate the cats into this room, so that the new cat gets some time to roam around the larger house area while the resident cat(s) is restricted, and then switch.

Make sure the cats have everything they need in their locations, such as litter box, food and water bowls, a comfortable bed, toys, scratching post, and anything else they enjoy. You may also want to purchase a door draft stopper and have it on hand in case the cats start to harass each other under the doors.

2. Let Them Meet Via Scent

Gray fluffy cat sniffing by the door

By now you should have started exchanging the towels with the cats. Each cat should have the other's scent on a towel or blanket that you place near their bedding. Says Jones, "I recommend putting the scented items near the bedding, not on it so the cat doesn't feel threatened or displaced by scent of the other cat."

3. Feed Them On Either Side of the Door

To start actually introducing the cats, you want to have them sense each other through the crack at the bottom of a door. To do this, "choose a special meal they get every day and really love, such as canned food or special treats."

Move Food Bowls Toward the Shared Door

You want to gradually move the bowls from their current location toward the door, separating them until their food dishes are right on each side of the door. Let them approach their dinner on their own time and let them eat as slowly as they like.

Move the bowls a few inches to a foot until the cats are eating normally for several meals in a row before moving the bowls again. Jones advises, "Some cats may take a couple of hours, others may take months to get the bowl to the door."

Stick With a Feeding Schedule

Repeat these feedings at scheduled times so the cats develop a pattern. Jones has cat owners do this, "As many times per day as possible, for example, you can break breakfast into three small breakfasts, and so on."

Monitor the Cats for Stressed Body Language

If you notice one or both cats showing stressful body language like growling, hissing, or ears back, move the bowls further away from the door until they are calm. 

You can try making the food extra enticing with some cut-up boiled chicken or some wet cat food and repeat the feeding, but this time at a further distance.

Gradually Get Closer

Slowly move the bowls closer to the door so long as everyone is calm.

Remove the Draft Stopper

If the cats have been eating on their respective sides without any issues, back the bowls up several feet and then remove the draft stopper. Then, repeat the steps above.

Related: Increase Your Cat's Calm With These 8 Easy Methods

4. Allow the Cats to See Each Other

If the cats seem generally calm and relaxed after a few days of eating on either side of the door, you can now try to let them see each other while eating their meals.

Place a Tall Baby Gate in the Doorway

Put a tall baby gate or stack two or three gates in the door that was previously separating them so that the cats can see each other but still not touch. You want to make sure the gate is high enough that they can't jump over.

Move Their Food Bowls Toward the Gate

Follow the steps for feeding them their meals and move the bowls back to the starting point. Gradually work on moving the bowls closer and closer until they are eating on their respective sides of the gate without incident.

Need to Know

During times when they are not eating, and you are not working with them, keep the door closed.

Try Short Sessions With the Gate

In addition to feeding them their meals this way, you can also have small sessions where they see each other without meals. This works best if you have two people, with one person each sitting with a cat.

Each person will give some extra delicious treats to the cats while they see each other, or they can play with the cat with a wand toy or brush them. Whatever it is, the activity with the cat should be something that individual cat enjoys.

Create a Positive Experience Around Seeing the New Cat

If you're by yourself, sit against the baby gate so you can easily reach both cats to hand or toss them treats or handle a fishing wand toy.

The idea is to pair something the cats love with seeing this new strange cat. Continue doing this in small increments of time of no more than 5 to 10 minutes a few times a day.

Increase Their Face-to-Face Time

If the cats are doing well, then you can do this for longer increments of time, and you can move about the house. You still want to supervise so you can run in and shut the door if need be, but you do not need to sit there with the cats. The idea is to get them used to each other without your presence.

Remove the Baby Gate During Meal Times

Gradually increase the amount of time that you are not supervising closely and close the door only when you're away or asleep. If all is going well and there are no incidents, remove the baby gate during meal times and put it back when they are done eating.

Related: Cats Playing vs. Fighting: 6 Ways to Tell & How to Break Up a Fight

5. Finally: The Cats Meet!

If everything has gone well and the cats appear generally relaxed, it's time to move forward. Note that it's not abnormal to see some signs of displeasure, such as hissing or backing away at first.

Two Cat Fighting on Bed
Need to Know

If you do see hissing or backing away, this means you are going too fast! Go back one step and repeat that step until everyone seems fine, and then proceed to the next.

Repeat Introduction Without Baby Gate

Repeat the steps above in Section Four, but remove the baby gates. Allow the cats to come up to each other and keep a keen eye out for their body language and signs of stress.

Use Positive Reinforcement

Continue providing them with treats and talk to them both in a happy but calm tone of voice. Do these sessions for no more than 10 minutes a few times a day for a few days.

Extend Their Face-to-Face Time

If these sessions are going well, then try to extend the amount of time until the cats can be fine exploring the house on their own while tolerating each other's presence.

6. Don't Leave New Cats Unsupervised

Even if the cats are do great, you should not leave them alone unsupervised in the beginning until you're fully confident the cats will be fine. However, you don't have to separate them with a closed door. Instead, use the tall or stacked baby gates so they can still have the benefit of seeing each other, but they won't be able to get into a scuffle if they have a disagreement.

Introducing a New Kitten to an Older Cat

It is very normal for adult cats to be upset about the addition of a new pet into the household. The Humane Society of the United States offers these tips to help your current cat and the newcomer.

Get a Head Start

One of the best ways to ease the transition of bringing a new cat into your home is to familiarize each cat with the other's scent beforehand. If you're able to, request a blanket from your kitten's foster parent or rescue that the kitty's been sleeping on, and give the foster a blanket your cat has been sleeping on. Let each cat sleep on the new blanket with the other cat's scent for about a week.

A Room of Their Own

Like with adults, keep the cat and kitten completely separated from one another for the first week after the new kitten arrives. Spend time playing with the kitten in their room, but be sure your resident cat still gets the attention they're used to.

Swap Spaces

After the initial week of separation, confine your resident cat to the kitten's room while the kitten explores the rest of the house. You can do this several times a day, but only when you're there to supervise. This further exposes each cat to the other's scent. Repeat the process over several days.

Using a Crate for Introductions

If you don’t have a separate room to house your kitten, feline welfare organization International Cat Care offers some suggestions for using a cat crate to help the cat and new kitten move from initial visual contact to interacting freely.

You’ll only want to do this if the kitten already feels safe and comfortable in their crate. According to International Cat Care, “Never introduce a cat or kitten by confining one or both to a cat carrier – they do not provide an opportunity for retreat.

Allow your resident cat into the room to sniff around and see the kitten through the mesh of the cage. Make sure a portion of the crate is covered, so the kitten can hide there if they get overwhelmed. The next step is to open the cage door and allow the kitten to venture out. Watch your other cat's reaction closely and if they show any sign of aggression, immediately put the kitten back in the cage.

Be Patient

Your goal in the beginning is simply to have the cats be in the same room without one attacking the other or too much hissing and yowling going on. They don't have to be best friends at first. You simply want them to cohabitate without any major problems. Once you get through this initial phase, the cats will likely learn to love one another and reside in harmony.

Handling Expectations With Cat Introductions

Kitten placing paw on other kitten

While it would be much easier for cats to get along right away, meeting a new cat can be stressful for a resident cat. Jones says it's common for cat introductions to lead to, "fear, stress, anxiety that worsens other issues like litter box avoidance, and fights that cause injury or are non-stop." This is why it's essential to take the time to follow the steps for introductions that minimize stress, even if it does seem like a long process. If you're having trouble, Jones recommends seeking help from a behavior professional who can work with you through the process. Your cats will thank you for it!

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Introducing Cats to Cats & Cats to Kittens: A Complete Guide