How to Introduce a New Kitten to an Existing Cat — 14-day plan
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Rushing the introduction is the #1 cause of long-term cat-vs-cat tension. Here's the slow-and-boring plan that actually works.
Introducing a new kitten to an established cat is one of those things where every week of patience prevents months of hissing. Skip the gradual phase and you can create territorial resentment that never fully resolves.
Before the kitten arrives
- Set up a kitten sanctuary room (spare room, laundry, walk-in robe) with its own litter tray, food, water, scratching post, bed. The kitten will live here for the first 5–7 days.
- Have two new unwashed towels. You'll use them to swap scents.
- Plug in a Feliway Friends diffuser (specifically Friends, not Classic) in the shared living area 2–3 days before the kitten arrives.
Days 1–3: Scent only
The kitten lives in the sanctuary room. The resident cat does not see or smell it directly. Each day: 1. Rub one towel on the kitten's cheeks (scent glands) and place it under the resident cat's food bowl. 2. Rub the other towel on the resident cat's cheeks and place it under the kitten's bowl. 3. Both cats now associate the other's scent with mealtime.
Watch for hissing at the towel — normal for 1–2 days. Continue until both cats eat calmly.
Days 4–7: Swap rooms
While the resident cat is outside the kitten room, let the kitten roam the main house for 30 minutes. Then swap — confine the resident cat in the kitten room (with the kitten back in the main room). They're smelling each other's full territory now.
Days 8–10: Visual, no contact
Use a baby gate or prop the door open 5–10 cm. They can see each other but not reach through. Do this at feeding time — they're distracted and associate the other's presence with food.
Short sessions: 10–15 minutes. Multiple times a day. End before either cat is stressed.
Days 11–14: Supervised contact
Open the door for short supervised sessions. First session: 10 minutes. Cats will probably hiss, swat once or twice, retreat. Don't intervene unless there's sustained attack.
Increase session length daily. By day 14 they should tolerate each other in the same room.
When it's not working
Some cats — especially adult cats who've lived solo for 5+ years — genuinely do not want a housemate. Warning signs after week two: - Resident cat is hiding 90%+ of the day - Litter-box avoidance (peeing outside the tray) - Loss of appetite lasting 48+ hours - Sustained aggressive attack (not just hiss-swat)
If you see these past week three, consult a feline behaviourist before the pattern sets. AVSAB-certified behaviourists in AU: ~$180–350 per consult. Cheaper than re-homing.
Last updated 2026-04-23 · Not veterinary advice — always consult your vet for medical concerns.