Cats stopped using the litter box?

I have two cats and one of them (or maybe both) randomly stopped using the litter box partly of the time. They are slightly older cats, 10 and 11 yrs. old, but both of them still move perfectly fine and don't feat senile in any other way. Their litter box is always verbs and fresh (it's automatic.) How can we stop this/Any ideas why they're doing it?
I enjoy had problems before and in my research it be recommended to have at least one litterbox per cat. I had two litter boxes for my two cats and tried to cut hindmost to just one box. After the futon was peed on I put the second one support where it was. That didn't solve the problem completely so they don't have access to the futon in a minute. I'm still trying to figure that out.
The two most common reason cats stop using the litter box are:
1) The box isn't clean enough for them. They get pickier as they attain older so you might want to clean more often and/or incorporate a second litter box to give them a choice.
2) Illness. Cats are particularly prone to CRF (Chronic Renal Failure) as they return with older, so you might want to rule out illness before determining it's a behavior problem.
Good luck.
they're probably to good-for-nothing since they are so old
The only idea since you said that the litter box is other clean, is that the cats may be looking to mark their territory. That's really adjectives I have...Otherwise maybe it's their diet and you are feeding them things that hand over them diarrhea...I'm sorry but that's all I got! I would take them into the vet, I hope they gain better!!


And 11 isn;t too old! My cats are 19 and they still use their litter box!
I would take both of them to the vet if they keep hold of that up.
Sometimes it can indicate a urinary tract infection. You might want to go to the vet.
my cat started to piss on the carpet in front of the box because it hurt her to pee..they probably hold a urinary-tract infection...it is caused by having their food changed all the time and ingestion lots of salty foods like cat treats and canned food, clutch her to the vet and get meds. buy food that is urinary tract food (Purina One) Wal-mart is cheapest.
that really truly sucks
Answers:    Litterbox issues are a real challenge. Definately enjoy them checked out for infections but I do find that most issues with litterboxes have more to do with the cleanliness of the box itself. Even though you say-so it is an automatic unit, it still needs to be cleaned aka washed out. Try doing that esp. as you own two kitties. Often they can be offended by another's poop.
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