How to Introduce a New Cat to Your Resident Cat: Step-by-Step

The first few weeks of a cat introduction set the tone for the entire relationship. A careful, patient approach makes all the difference. A successful introduction is rewarding; a rushed one can create lasting hostility.

Before the new cat arrives

Set up a sanctuary room

The new cat needs a dedicated space containing food and water, a litter tray separated from the food, a comfortable sleeping spot, a hiding option such as a box or igloo, and a pheromone diffuser plugged in before arrival. Choose a room the resident cat does not regularly pass through.

Prepare the resident cat

Plug in a cat calming diffuser in the main areas where your resident cat spends time, ideally at least a week before the new cat arrives.

Stage 1: Sanctuary (Days 1 to 7)

The new cat remains in their sanctuary room while the resident cat continues normal activities elsewhere. Both cats learn of each other's existence through sounds and scents without any direct contact. The new cat may hide initially. This is normal. The resident cat may sniff at the door or carry on as usual. Both responses are fine.

Stage 2: Scent swapping (Days 5 to 14)

Rub a soft cloth on the new cat's cheeks and chin, then place it near the resident cat's food bowl. Do the reverse with the resident cat's scent in the sanctuary. Also swap sleeping blankets. Observe reactions carefully. Progress only when both cats respond neutrally or positively to each other's scent.

Stage 3: Visual contact (Days 10 to 21)

Once scent swapping is going well, introduce visual contact. Use a baby gate in the doorway, or prop the door open a few centimetres. Feed both cats simultaneously on either side of the barrier. Initial hissing and posturing through the barrier is completely normal. Hissing should decrease over multiple sessions. Do not progress until both cats remain reasonably calm at the barrier.

Stage 4: Supervised interaction (Week 3 onwards)

Open the sanctuary door for brief supervised periods of five to ten minutes, always ending before any tension peaks. Have a piece of cardboard ready to create a barrier without using your hands. Ensure multiple escape routes so neither cat is trapped. Give each cat separate attention afterwards. If interaction goes poorly, separate immediately and return to Stage 3. If it goes well, gradually extend the time.

Stage 5: Unsupervised cohabitation

Only progress to leaving them unsupervised when both cats consistently stay relaxed during supervised sessions. Keep the sanctuary room available as a retreat option for several more weeks.

Common troubleshooting

New cat will not leave the sanctuary room: Do not force exploration. Some cats take two weeks to feel confident enough to venture out.

Resident cat becomes destructive or stops eating: They are stressed. Slow the introduction, maintain their routine, and increase one-on-one play time with them.

Cats still hissing through the gate after several days: This is normal. Continue Stage 3 longer. Progress is measured in weeks, not days.

One cat becoming fearful or being chased: Separate fully and consider contacting a registered cat behaviourist.

Related articles

• Scent Swapping: How and Why to Do It
• How Long to Keep Cats Separated
• Cats Hissing at Each Other

Frequently asked questions

How long does it take for cats to get used to each other?

Most cats reach a stable, tolerant relationship within 8 to 12 weeks of a well-managed introduction. Some bond faster; others need six months or more. The process cannot be rushed.

Is hissing during introduction normal?

Yes. Hissing during introduction is completely expected and does not mean the introduction is failing. The resident cat is communicating boundaries. Slow the process if hissing is intense, but do not panic at hissing itself.

What if my resident cat will not accept the new cat?

Separate completely and restart scent swapping slowly. If significant aggression persists after three to four months of careful management, consult a registered cat behaviourist.