Cat guide ·
How to Introduce a New Cat to Your Cat: A Slow, Calm Step by Step Plan
By the Brus Crew, a family with a house full of cats
How do you introduce a new cat to your cat? Slowly. Keep the newcomer in their own room at first, let the two cats get used to each other's smell through a closed door, then swap scents, and only then allow short, calm, supervised meetings. Rushing it is the most common mistake. Most cats need days or weeks, and a few need longer, to settle into sharing a home.
Key points
- Cats rely on smell and territory, so a slow introduction works better than putting them together on day one.
- Give the new cat a separate "safe room" with food, water, a litter tray, a bed and somewhere to hide.
- Swap scents (bedding, a soft cloth) before the cats ever meet.
- Keep first meetings short and positive, and go back a step if either cat is very stressed.
- Ask your vet to check a new cat, and check vaccinations and health first, before they meet your resident cat.
Before the new cat comes home
Pick a spare room that your resident cat does not use as their main spot. Set it up with a litter tray, food and water bowls, a bed, a scratching post and a box or blanket to hide in. If you can, ask the rescue or breeder for a blanket that smells of your new cat. Our general guide to looking after a cat lists the basics every cat needs.
Book a vet check for the newcomer, and make sure vaccinations are up to date before they share space with your resident cat. Your vet can also advise on parasite treatment and on any health tests that suit your cat.
Step by step
1. Keep them apart at first
Leave the new cat in their safe room for several days. Let your resident cat sniff at the closed door. It is normal to see some curiosity, and some hissing or growling.
2. Swap scents
Rub a soft cloth on one cat's cheeks and leave it near the other's food or bed. You can also swap their bedding. The aim is for each cat to link the other's smell with something nice. Reward calm behaviour with treats or a favourite meal.
3. Feed on either side of the door
Put their food bowls near the door, a little way back at first and then closer over a few days. Eating together, with a barrier in between, helps build good feelings.
4. Let them see each other
Use a baby gate, or a door open just a crack, so they can see each other without being able to fight. Keep it short and end on a good note.
5. Short supervised meetings
Open the door and let them explore together for a few minutes. Have another person there, and use toys and treats to keep the mood relaxed. Never grab or force two cats together. If things get tense, calmly distract them and go back a step.
6. Gradually share the house
Extend the time together, and make sure each cat has their own food, water, litter tray (the usual advice is one tray per cat plus one extra), bed and high places to retreat to.
What is normal, and what is not?
Some hissing, growling, staring and puffed-up fur is normal early on. Watch for these instead, which mean you should slow down:
- fighting or chasing that does not stop;
- one cat hiding for days, refusing to eat or using the litter tray less;
- spraying or toileting outside the tray;
- constant blocking of food, water or doorways.
If problems carry on, speak to your vet, who can check for health causes and may refer you to a qualified cat behaviourist. Our guide to cat behaviour covers body language in more detail.
How long does it take?
It varies. Some cats are friendly in a few days, while others take a month or more to settle, and some simply learn to share space politely without becoming close friends. Younger cats and kittens often adjust more quickly. A new kitten and a grumpy senior are a different challenge, and our senior cat health guide may help you think about an older cat's needs.
Look at our cat breed guides too if you are still deciding which cat to bring home.
Questions people ask
Should I let my cats fight it out?
No. Fighting can injure them and make things worse. Separate them calmly and go back to an earlier step.
Is it better to get a kitten or an adult?
It depends on your resident cat. Many adult cats cope better with a kitten of a similar energy level, or a cat of a similar age. A rescue can often tell you how a cat has got on with others.
How many litter trays do I need?
The usual advice is one per cat plus one extra, placed in different spots.
Can I use a calming plug-in?
Some people find synthetic pheromone products help. They are not a magic fix, so combine them with a slow introduction and talk to your vet if you are unsure.
What if my resident cat will not stop hissing?
Hissing is a way of saying "give me space". Slow down, keep rewarding calm moments and give it time.
