How to Introduce a New Cat to Your Cat

We may earn a commission when you buy through links on this page, at no extra cost to you. Learn more

A second cat is exciting for you and, at first, unsettling for the cat already living there. Cats are territorial, and a stranger in their space can lead to hissing, hiding or fights. A slow introduction lets both cats get used to each other one sense at a time: smell, then sight, then face to face. Here is how to set up the house, the steps to follow, when to slow down, and how to share resources.

How we wrote this: the steps follow Battersea’s guide to introducing cats, Best Friends Animal Society’s advice on introducing cats to each other and PDSA’s vets’ page on preventing stress in cats. We put their advice in our own words and mark our own tips with “in our view”. All were checked on 2 November 2026. We did not test any of the products named here ourselves, and we do not show prices or ratings. This is not veterinary advice: if a cat is injured in a fight, stops eating or stops using the litter box, call your vet.

1. Set realistic goals

Battersea points out that cats do not naturally seek out other cats as company. Many pairs never become close friends, and two cats that calmly tolerate each other is a good result. PDSA adds that sharing space and resources with other cats is a common source of stress.

Battersea says some stages can take weeks or even months, at the pace of the more worried cat. In our view, plan for weeks rather than days, and do not judge the outcome by the first meeting.

2. Think about the match before you adopt

Both Battersea and Best Friends suggest choosing the new cat with your resident cat in mind. Points they raise:

• Age and energy. A bouncy kitten or young cat can wear down an older, quieter cat.
• Temperament and habits. Best Friends suggests matching a playful cat with another player and a sun-lover with a calmer cat.
• History. A cat that has lived happily with other cats before is more likely to settle, according to both sources.

Battersea says the same steps work for a kitten. In our view, ask the shelter how the cat behaved around other cats.

3. Prepare a base room for the newcomer

Before the new cat arrives, set up a quiet room that your resident cat does not depend on. Battersea and Best Friends list much the same contents:

• A litter box, placed away from the food and water.
• Water and food bowls, set apart from each other.
• A comfortable bed and a few places to hide.
• A scratching post and some toys.
• A door that closes securely.

Best Friends suggests keeping the new cat’s area smaller than your resident cat’s, with hiding spots in both. It likes large cardboard boxes with a hole cut in two sides, so a cat inside always has a second exit.

The new cat goes straight into this room and stays there while it settles; Battersea says it should remain its retreat throughout. Our guide on how to get your home ready for a new kitten has a fuller setup list.

4. Keep your resident cat’s routine the same

Best Friends suggests giving the new cat a little of your time daily but your resident cat more, so the change feels like a plus. Watch for stress such as hiding, aggression, eating less or a lot of yowling; if it lasts more than a few days, or a cat stops eating, call your vet.

PDSA lists changed routines, moved litter boxes or bowls and lost hiding places among common stress triggers. In our view, do not move your resident cat’s litter box, bed or favourite perch to make room.

5. Swap scents before they meet

Battersea suggests starting a scent swap after two or three days: put a blanket your resident cat has slept on into the new cat’s room, and move one from the new cat to your resident cat. Best Friends describes gently rubbing a soft cloth on each cat’s cheeks, where scent glands sit, and offering it to the other cat.

Best Friends also suggests a room swap once both cats are calm: move the new cat into another prepared room for a while and let your resident cat explore the base room. Each cat then meets the other’s scent without meeting the cat.

Both sources pair this stage with something nice, such as a treat or a game. Best Friends describes placing the bowls on each side of a closed door, starting a few feet back and moving them closer as the cats stay relaxed. That is about placement only; for what and how much to feed, ask your vet, or see inthekibble.com for food topics.

6. Add sight, with a barrier in between

When both cats are relaxed about the other’s smell, move on to sight. Battersea suggests opening the base room door a little and fixing it so it cannot swing wider, or using a baby gate. Best Friends describes a door propped open just a couple of inches, or a baby gate.

In our view, a determined cat can hop a standard baby gate, so pick a tall one and stay in the room. Our best dog gate guide covers tall gates.

Keep these sessions short. Battersea suggests having someone play with each cat or offer treats, so the cats focus on something pleasant rather than on each other. If either cat stares, growls or runs to hide, Battersea says to go back to scent swapping for a few days.

7. Move to short, supervised meetings

If the barrier sessions go well, open the door and let the cats share a room. Best Friends suggests starting with the cats at opposite sides of a large room, each with a person playing with it, and closing the distance a little over several sessions. Battersea says to keep meetings brief and never force contact; two cats ignoring each other is a very good sign.

A wand toy is useful here because it keeps a cat busy at a distance from you and the other cat. See how to play with a cat using a wand toy. Battersea adds two firm rules for this stage:

• Keep the base room open so the new cat can leave whenever it wants.
• Do not hold either cat back with a lead, harness or carrier. Each cat needs to be free to come closer or move away.

Some hissing or a swat is normal, according to Battersea. Ongoing growling or either cat turning aggressive means stepping back to the previous stage.

8. Know when to slow down, and how to break up a fight

Battersea lists quieter signs of tension that are easy to miss: one cat sitting in the way of the litter box or cat flap, staring, low growls when the other cat is near, or leaving the room as soon as the other cat walks in. If you see these, add resources or slow the pace.

If a fight breaks out, Battersea warns against reaching in with your hands, as you can easily be hurt. Slide something between them to block their view instead, such as a large piece of cardboard. In our view, keep a flattened box within reach during early meetings. After a fight, separate the cats and go back several steps.

9. Give each cat enough of everything

Battersea’s key to a calm multi-cat home is space, choice and enough resources that no cat has to compete. Its list:

• Litter boxes: one per cat plus one more, in quiet, private spots.
• Feeding spots: one per cat, set apart, since cats do not naturally choose to eat side by side.
• Water: several bowls around the home, away from food.
• Scratching posts: several, including near doors and cat flaps.
• Hiding places and high spots: boxes, covered beds, shelves or a cat tree with several levels.

PDSA notes a cat may feel stressed if it has to pass another cat to reach its bowl or litter box. In our view, spread the litter boxes across different rooms rather than lining them up together, so one cat cannot guard them all from one spot.

For two cats that means three boxes. The IRIS USA High Sided Litter Box is an open box with tall sides that act as a scatter shield, according to its listing, and our best litter box for multiple cats guide compares more options. For height, the Feandrea 37.8-Inch Multi-Level Cat Tree has a cave, basket, padded perch and sisal posts on a small footprint with an anti-tip kit, according to its listing. See best cat trees for indoor cats for taller trees, and how to stop a cat scratching furniture for scratcher placement.

Battersea also suggests one-to-one time with each cat every day, and calm shared activities at a distance, such as eating in the same room but well apart.

When to call your vet or a behaviourist

Call your vet if a cat is hurt in a fight, stops eating, starts toileting outside the litter box, or shows a sudden change in behaviour. PDSA notes that many signs of stress, such as hiding, aggression, appetite changes or toileting problems, can also be caused by illness, so a vet check comes first. Ask your vet before relying on any calming product; we make no claims for them. If the cats still do not get on after a slow, careful introduction, Battersea and Best Friends both suggest help from a qualified feline behaviourist. Some cats are simply not suited to sharing a home, and that is not your fault. Bringing in a dog as well? See how to introduce a cat to a dog.

FAQ

How long does it take for two cats to get along?

It varies. Battersea says some stages take weeks or months, at the more anxious cat’s pace. Some pairs become friends; others only learn to share space calmly.

Is it normal for cats to hiss when first introduced?

Yes. Battersea says some hissing or swatting is not unusual. Constant growling, chasing or fighting means you should go back a step and slow down.

Should I let my cats fight it out?

No. Fights can cause injuries and make the cats more wary of each other. Block their view with cardboard or a cushion rather than your hands, separate them, and restart from an earlier step.

How many litter boxes do I need for two cats?

Battersea recommends one per cat plus one extra, so three for two cats, placed in private spots.