How to Introduce a New Cat to Your Resident Cat

By Hannah Pryce · Published Sep 17, 2026 · 7 min read

In this guide

Step 1: A separate base camp
Step 2: Scent swapping
Step 3: Seeing without touching
Step 4: Supervised time together
Resources reduce conflict
If things go wrong

Cats are territorial, and a newcomer can feel like an invasion. Putting two unfamiliar cats together and "letting them sort it out" often leads to hissing, fighting, and long-term stress.

A gradual introduction over one to several weeks takes patience, but it greatly improves the chances of a peaceful — or even friendly — relationship.

Step 1: A separate base camp

Set up a room for the new cat with food, water, a litter box, a bed, a scratching post, and hiding places. Keep the door closed. This lets the new cat settle and the resident cat keep the rest of the house.

Step 2: Scent swapping

Cats recognise each other by smell first. Swap bedding between the cats, and gently rub a soft cloth on each cat's cheeks and leave it near the other cat's food. Reward calm reactions with treats.

After a few days, let the cats swap spaces while the other is shut away, so each can explore the other's scent.

Step 3: Seeing without touching

Use a baby gate, a screen door, or a door opened a crack to let the cats see each other briefly during meals or play. Keep sessions short and positive, and increase their length gradually.

Step 4: Supervised time together

When both cats are relaxed during sightings, allow short supervised sessions in the same room. Use play and treats to keep things positive, and separate them calmly before tension builds.

Warning signs: flattened ears, puffed tail, staring, growling, or swatting
Good signs: relaxed body language, sniffing, slow blinks, ignoring each other

Resources reduce conflict

Provide plenty of resources in different places: food bowls, water bowls, litter boxes (one per cat plus one), beds, and high perches. Competition for resources is a major cause of tension between cats.

If things go wrong

If fighting breaks out, do not use your hands to separate cats. Make a noise or put a cushion between them, then separate them and go back a step. If problems continue, ask your vet or a qualified feline behaviourist for help.

This is general pet-care information, not veterinary advice. Every animal is different — if you are worried about your pet's health or behaviour, contact your veterinarian. In an emergency or a suspected poisoning, call your vet or an animal poison-control line immediately.

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