Why Won't Kitty Use Her Litter Box?

If your cat is not using her litter box, it may be because:

Her litter is too dirty
This is the most common reason. Clean out her litter more often and see if this helps.

Stress
Perhaps your feline is anxious about a move, new furniture or carpeting, a new person or animal in the house ...

She is attracted to a previously soiled location.
If your cat keeps returning to one spot, it may be a spot where another pet previously soiled. Make this spot less attractive to your pet by: Put her food bowl there. Cats do not like to eliminate at the same place they eat.

Neutralize odor
A half and half solution of white vinegar and water will help to rid the area of any smell.

Cover the area with a plastic sheet.
This will make it unpleasant to your kitty and discourage her from eliminating there.
Your kitty may not like her brand of litter. Cats can be finicky; if you have recently changed the type of litter used, change it back. If not, experiment with other brands until you find one that kitty likes.

Your cat may not know where her litter box is. Especially common with young kittens or after a move. Place the litter box in a clean, accessible, and relatively quiet location and show your cat where it is. You may want to put the box on the same floor as the cat to begin with.

Your cat is marking his territory. Male cats sometimes spray urine to mark their territory; this is yet another good reason to be sure you neuter your pet (neutered males are less likely to spray).

If your cat has always used her litter box and has recently started to "mess", consider taking her to the vet to rule out any medical conditions.