How to Introduce a New Cat to Your Resident Cat Without Fights

By Tailwisp Editorial TeamUpdated October 20, 20264 min read

Bringing a new cat home is exciting for you and often alarming for the cat already living there. Cats are territorial, they rely on scent and routine, and they do not automatically welcome newcomers. A slow, structured introduction gives them the best chance of becoming friends, or at least peaceful roommates.

Before the new cat arrives

Prepare a separate room for the newcomer, called a base camp. Put in a litter box, food and water, a bed, a scratching post, toys and a hiding place. A spare bedroom or bathroom works. Visit your vet first to check the new cat for illness and parasites, and make sure your resident cat is healthy and vaccinated, as outlined in cat vaccination schedule. Keep the new cat isolated for at least a few days, or longer if there are health concerns.

Make sure your resident cat has all it needs: a litter box, food, water, perches and hiding places of its own.

Step 1: Scent first

Cats identify each other by smell. Before they see each other, swap scents.

1. Rub a clean sock or cloth on one cat's cheeks, and place it near the other cat's food.
2. Swap bedding between the cats.
3. Let each cat explore the other's room when the other is out of it.

Reward calm responses with treats. If a cat hisses or growls at the scent, go back and give more time.

Step 2: Feed near the door

Place food bowls on each side of the closed door, starting far enough away that neither cat reacts. Over several days, move the bowls closer. The cats link the other's smell with something pleasant. If either cat stops eating or stares tensely, move the bowls back.

Step 3: Sight without contact

Open the door a crack, or use a baby gate, a screen or a see-through barrier, and let the cats see each other briefly. Keep sessions short, and distract with a wand toy or treats. Gradually lengthen the sessions as long as both stay relaxed. Watch for ears flattened, a puffed tail, staring, growling or stalking. If these appear, close the door and try again later. Read about signals in why do cats hiss.

Step 4: Supervised time together

Once the cats are calm at the gate, allow supervised time in the same room.

• Use play, treats or meals to keep the mood positive.
• Keep sessions short, and end before tension rises.
• Have a towel or cardboard ready to separate cats safely if a fight starts. Never use your hands.
• Allow both cats an escape route and high places.

Increase the time over days or weeks. Many cats are ready after one to two weeks, but some need a month or more.

Step 5: Shared household

When the cats are relaxed together, gradually allow shared space. Keep separate food bowls, water, beds and litter boxes, and keep adding vertical space. Do not leave them alone together until you are sure they are safe, and continue to supervise at first.

Signs of progress and trouble

Spraying or inappropriate urination can follow introductions. See why is my cat peeing outside the litter box.

Resources for every cat

Reduce competition by providing:

• One litter box per cat plus one extra, in different rooms. See how often to clean a litter box.
• Separate food and water stations, out of sight of each other at first.
• Multiple perches, cat trees and hiding places.
• Scratching posts in several areas.
• Individual play and attention for each cat.

Our indoor cat enrichment ideas can reduce tension.

Special cases

Kitten and adult. A kitten's energy may overwhelm an older cat, so provide breaks and a kitten-free space for the adult. See how to socialize a kitten.

Senior cats. Older cats may be less tolerant. Move slowly, and make sure the senior has easy access to resources.

Cats and dogs. Introduce through a gate, keep the dog on a leash and reward calm behavior. Never leave them unsupervised until you are certain they are safe.

When to get help

If cats fight, if one is terrorized, if appetite or litter box use changes or if there is no progress after several weeks, talk to your vet. Pain, illness and stress can cause aggression. A veterinary behaviorist can help create a plan. Use the US vet directory to find a clinic.