Here's some information from our members about this problem:
Here are some things to try for cats who poop outside of the litter box.
Pooping outside the box is often a sign that the cat is sick. So, a vet visit will be a good idea. If the vet rules out medical problems, try some of these solutions:
If they poop in the shower or bathtub, statistics have shown this is health related- a vet visit is warranted and quickly.
Pooping outside the box will often happen when the cat has had painful bowel movements. The cat associates the pain with the litter box and becomes afraid to use the litter box to poop in. If you notice that the feces are hard and dry, try adding a little Libbyâ€™s raw pumpkin to her diet or give a little hairball medicine on a daily basis until the stool becomes a little softer.
There are many cats who refuse to pee and poop in the same box. Simply adding a second box often solves this problem. (scoop both boxes daily)
Also, many cats will do this if they don't think the box is clean enough. Just imagine yourself sitting and concentrating on a toilet full of excrement....not a pleasant thought! So, make sure you keep the litter box very clean (scoop daily).
For cats who poop just outside the box: This is often due to the box being too small for the cat so the cat stands in the box, but her bottom hangs outside while pooping. Switching to an extra large box (such as a rubbermaid underbed storage container) will solve this problem.
Also...she may be telling you that she just isn't comfortable with where you have the boxes right now. It is possible that if you put a second box in a completely different room, she may start using it instead of pooping where she is pooping. If the boxes are in a place where she feels vulnerable while she is having to sit and concentrate she won't use the box there. A quick pee in a scary spot isn't as uncomfortable as taking a poop, which takes longer and makes the cat feel more vulnerable. For some cats, they prefer their boxes to be out in the open so they can see the comings and goings of others...this way they can easily escape if they feel it is necessary. Other cats prefer hidden boxes where no one can see them while they are doing their thing. If the litter boxes are in a closet...this may be her way of telling you that at least one of them needs to be in a more open place. If this is the case, you can put it in a corner of a room and then surround the box with pretty house plants so that it isn't noticeable. Or vice versa; if the boxes are in an open spot, you might need to move one to a more hidden area.
if a cat is pooping on a familiar object it is probably stress related. You then have to find out where that stress is and eliminate it.
What are you feeding your cat? If it is cheap not very nutritious the fumes could be noxious to your cat and make him go elsewhere.
Using litter box liners? Throw them out, they annoy most cats as they make noise and get caught in their claws.
The pan must be far enough away from the cat's food and water
If using clumping litter, check between the pads of the feet for small balls of litter. If a cat steps in pee, then covers it, these balls sometimes accumulate causing problems for the cat.
Is your cat happy with the litter? One way to tell is watch as she digs in it, the more she digs and the more the litter flies, the happier the cat is.
Last but not least, try putting a box where she is defecating, and if she starts using it regularly then you can work on moving it to your desired location. Move it tiny bits at a time, like 1-2 inches per day, so she doesn't really notice that it's moving. Little by little you'll get it to the place you like.