A new sibling for your cat: how to introduce two cats step by step

It's lovely to imagine a home where two cats curl up and sleep on the same sofa. But in the cat world, that picture doesn't happen on its own. According to Cats Protection's behavior expert, the most common reason newly adopted cats are returned to the charity is that they don't get along with the cat already in the home, and this often happens within the first couple of days. The good news: a slow, planned introduction greatly improves the chances that two cats will accept each other. The steps in this article come from the advice of International Cat Care, Cats Protection and Blue Cross.

First ask: does my cat want a friend?

According to International Cat Care, cats are naturally solitary animals; even with the most careful introduction, some don't want to live with another cat. Cats Protection also says cats often prefer to be the only pet in the household. If you think your cat is lonely, the charity says that what it most likely wants is a bit more play and attention from you.

When deciding, think about your resident cat's age and personality. According to Blue Cross, cats that have lived alone for many years, or that haven't gotten along with other cats in the past, find it harder to adjust. Cats Protection also points out that cats reach social maturity between 18 months and 4 years of age, and that they can grow apart during this period.

Step 1: A room of its own for the new cat

When the new cat comes home, it isn't let loose in the house right away. International Cat Care recommends choosing a room your resident cat doesn't use and that you don't need to go into all the time. This room should have:

• Food and water
• Comfortable resting spots and a bed
• Hiding places
• A litter box
• Toys and a scratching post

According to International Cat Care, these things should either already belong to the new cat or be brand new. The smell on the resident cat's belongings will unsettle the new cat; and the resident cat can get stressed when it loses something of its own, like a litter box. When setting up the room, the "base camp" list in our first week guide will also come in handy.

According to International Cat Care, it can take anywhere from a few days to a week or two for the new cat to settle into its room. Cats Protection's behavior expert also says there's no exact timeframe, but as a rough guide, the new cat should stay in its separate room for at least a week.

If the cat has gotten used to its room, it will rub against you and purr when you come in, play with its toys, and eat and use the litter box normally. If it keeps scratching at the door or meows for minutes at a time, it may be frustrated in a single room; in that case International Cat Care suggests opening up another room or hallway for it, or, if that isn't possible, starting the introductions a little earlier.

Step 2: Scent swapping

According to Cats Protection's behavior expert, scent swapping is the most important stage; it should take up the biggest part of the process, yet it's often rushed or skipped altogether. Cats recognize each other by scent; the goal is for them to create a shared scent and see each other as members of the same group.

1. Swap bedding: International Cat Care recommends putting a piece of each cat's bedding (a blanket, for example) into the other cat's bed. Make sure both cats still have other places to sleep.
2. Collect scent with a cloth: According to Cats Protection, gently wipe a clean cloth around one cat's cheeks and forehead, then leave the cloth in the middle of the floor in the other cat's room. Putting the cloth on the floor instead of holding it out to the cat gives it the choice to sniff it or ignore it.
3. Refresh it every day: Scent fades over time. Cats Protection recommends topping up the cloths once a day.
4. Mix scents with your hands: Blue Cross suggests stroking each cat separately without washing your hands in between, so that you mix their scents.

If the cat sniffs the cloth and then ignores it, that's a good sign. If it skirts around the edge of the room to avoid the cloth or hisses at it, don't rush; according to International Cat Care, this means you'll need to go through the next steps much more slowly.

Once scent swapping is going well, International Cat Care suggests an in-between step: let the cats take turns exploring each other's area without meeting face to face.

Step 3: A first look through the glass

If both cats are comfortable in the home and used to each other's scent, it's time for them to see each other. But with a barrier in between:

• A glass door, or a door left ajar just enough that the cats can't get through
• A tall baby gate (stair gate)
• A mesh screen

Cats Protection's behavior expert recommends keeping these sessions short, 5–10 minutes each time, and increasing the time very gradually. Don't pick the cats up and put them in front of the glass: according to Blue Cross, cats prefer to watch from a distance and approach in their own time.

If the two cats glance at each other now and then and go back to what they were doing, all is well. If you see hissing, growling, or ears turned to the side with a tense body, International Cat Care recommends calling the cat that started the negative behavior by name to lure it away. Never punish your cat for it; that only frightens it more.

Step 4: Face to face, under supervision

If the cats can comfortably see each other through the barrier, International Cat Care says you can quietly open it while the cats are busy with something else. Don't push the cats toward each other; the goal is for them to be comfortable side by side, not necessarily to interact. Make sure both cats know where they can escape to or climb up high.

If something goes wrong, put the barrier back and return to the previous stage; according to Cats Protection's behavior expert, going all the way back to scent swapping is best if needed.

Step 5: Short periods of free access

If the supervised meetings go smoothly, International Cat Care recommends first leaving the cats together unsupervised for just a few minutes; in between, the new cat goes back to its own room. If both cats are comfortable, this time gradually gets longer. Eventually the door to the separate room can stay open and the cats can come and go as they please.

Keeping the peace: one more of everything

According to Blue Cross, even cats that get along well find it hard to share feeding, sleeping and toilet areas. All three organizations make the same recommendation: one per cat, plus one extra, spread around different parts of the home. This rule also applies to food and water bowls, beds, scratching spots and high shelves. You'll find the details for litter boxes in our litter box guide.

Cats Protection also warns about bullying in multi-cat homes. Watch out if one cat stares at the other for long periods, pushes it out of its resting spot, pounces on it while it's asleep, or blocks doorways or the way to the litter box.

How long does it take?

According to Cats Protection, there's no way of knowing in advance; the process can take weeks, and some cats never want another cat in the house. According to Blue Cross, some cats adjust in a few days, others in weeks or even months. The one rule that doesn't change is to go at your cat's pace: according to Cats Protection, a rushed introduction could mean the cats never get along.

If you're struggling, or a relationship that started well has broken down, International Cat Care recommends asking your veterinary team for help; they can refer you to a qualified animal behaviorist.

Frequently asked questions

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Sources

• International Cat Care · Introducing cats
• Cats Protection · Introducing cats & kittens
• Cats Protection · Behaviour matters: cat introductions (The Cat magazine, Summer 2016, PDF)
• Blue Cross · Introducing cats

By Tüylüm · Published and last checked: October 26, 2026. Spotted a mistake? Write to [email protected] and we'll fix it right away. Photos are from Wikimedia Commons, used under the license shown below each photo.