How do I introduce a new cat to my existing cat?

Slowly. Rushed introductions are the main cause of lasting conflict between cats, and a relationship that starts badly can take months to repair or may never fully settle. Most successful introductions take one to several weeks.

Begin with complete separation. The new cat occupies one room with its own litter tray, food, water, bed and hiding places. The resident cat retains the rest of the home. Neither should see the other initially. This lets the newcomer settle in a small territory and lets both become aware of each other through sound and smell without confrontation.

Scent comes next. Swap bedding between them, or rub a soft cloth on one cat's cheeks and leave it near the other. Cats identify by scent far more than by sight, and the goal is for each to encounter the other's smell repeatedly in a context with no threat. Feeding both on opposite sides of the closed door builds a positive association.

Only when both are relaxed at the door should they see each other, ideally through a barrier such as a cracked door or a baby gate, for short periods.

First direct meetings should be brief, supervised, and ended before either shows tension. Ending early and repeating often beats letting a long session deteriorate.

Resources matter throughout. Provide separate litter trays, generally one per cat plus a spare, separate feeding stations, and plenty of vertical space and hiding spots, since the ability to withdraw reduces conflict.

Hissing and swatting during early meetings is normal communication. Sustained aggression, stalking, or either cat stopping eating or using the tray means going back a step and, if it persists, seeking advice from a vet or behaviourist.