You have a cat. Now a second one has turned up: a kitten from the street, or the shy tabby from the feeding spot who finally let you pick it up. You picture them curled up together. Your cat pictures an intruder.
Cats are territorial. To your cat, home is its patch, and a strange cat in it is a threat. Putting two cats in a room and letting them “sort it out” often ends in fights that are hard to undo. Going slowly gives them the best chance of getting along.
The short version
- Vet check first, especially for a street cat.
- Give the new cat its own room, with everything it needs.
- Let them get to know each other’s smell before they meet.
- Then short looks through a gate, then short meetings.
- Enough bowls, trays and beds for every cat, plus one. Never force it.
First: a vet check
A street cat can bring in fleas, worms and infections your cat could catch. Before they share a home, have the new cat checked over, treated for parasites, and tested for FIV and FeLV, two viruses that pass between cats. Our guide to adopting a street cat has the full list. It also helps if both cats are neutered: neutered cats tend to get along better.
Step 1: a room of its own
Choose a room your cat doesn’t use much, and keep the new cat there with the door shut. International Cat Care says it needs everything of its own: food, water, a bed, places to hide, a litter tray, toys and a scratching post. These should be new, or come with the new cat. Don’t borrow your cat’s things.
Keep your own cat’s routine as normal as you can. Feed it at the same times, in the same places, and give it the same attention.
The new cat needs to settle in before anything else happens. That takes anything from a few days to a week or two. It’s ready when it greets you, plays, rolls over, and eats, uses the tray and grooms normally.
Step 2: swap smells
Cats learn about each other by smell long before they need to see each other. So introduce the smell first.
- Swap bedding. Give each cat a piece of the other’s bedding. When both are relaxed about it, swap again.
- Mix their scent. The ASPCA suggests rubbing a towel on each cat’s cheeks and putting a treat on it, so the other cat’s smell comes with something good.
- Treats at the door. Give each cat treats and play near its side of the closed door. They can smell and hear each other, but not see or touch.
- Swap rooms. Once the new cat is confident, shut your cat away for a while and let the newcomer explore the house. Then let your cat explore the new cat’s room.
If either cat hisses at or avoids the other’s smell, slow down and give it more time.
Step 3: a first look
When both cats are calm about each other’s smell, let them see each other through a barrier: a stair gate, a mesh screen, or a door open just a crack.
- Keep it short, a few minutes, and end while both are still calm.
- Don’t pick either cat up or hold it there.
- If one cat gets upset, calmly end the session and try again another day.
- Make the sessions longer over several days.
Step 4: short meetings
When they can watch each other through the gate without any fuss, open it while you’re there. Start with a few minutes. Let them sniff, or ignore each other, which is fine too. Don’t force them together. Between sessions, the new cat goes back to its room. Little by little, let them spend longer together, until you can leave them alone.
If there’s a fight, don’t reach in with your hands. The ASPCA suggests dropping a big towel between them to block their view, guiding them apart, and going back to the gate stage for about a week.
Signs it’s going well, or not
Going well: relaxed bodies, sniffing noses, ignoring each other, playing, eating and using the tray as normal. Later, maybe sleeping near each other or grooming each other.
Slow down: hissing, growling, staring, a tense body with ears turned sideways or back, one cat hiding all the time, or a cat that stops eating or using the tray. Go back a step, and stay there longer.
Enough of everything
Cats don’t like to share, and a bossy cat can guard the only food bowl or litter tray and keep the other away. International Cat Care says every cat needs its own food and water bowls, bed, litter tray and scratching post, plus one extra, spread around the home. High places, like shelves and the top of a wardrobe, give a cat somewhere to watch from and get out of the way.
How long it takes
It can be days. It is often weeks, and sometimes longer. The ASPCA’s advice is patience: some cats take a long time to accept each other. Rushing usually means starting again.
Some cats never become friends, and that’s fine. Many live happily side by side, just ignoring each other. A few cats simply don’t want to share their home with another cat, and International Cat Care says recognising that matters for their welfare. If things don’t improve, talk to your vet, who may suggest a qualified cat behaviourist.
Questions people ask
How long does it take to introduce two cats?
Often weeks, sometimes longer. The new cat first needs a few days to a week or two to settle in its own room, and each step after that goes at the pace of the more nervous cat.
Is hissing normal when introducing cats?
A little hissing early on is common. It means one cat isn’t ready yet. Go back a step and give them more time with each other’s smell before trying again.
Can I bring a street cat home if I already have a cat?
Yes, but see a vet first. A street cat should be checked, treated for fleas and worms, and tested for FIV and FeLV before it meets your cat. Then introduce them slowly, starting in a separate room.
Snap both cats with Island of Cats. One day you might catch them asleep on the same sofa.
