male cat that sprays

Have you been keeping the litter box clean? Could he dislike the location (high traffic, no privacy, etc.)? Those are two more reasons I just read about. He's either marking his territory or he's angry about something. How young was he neutered? Before or after sexual maturity? Did he ever spray before he was neutered?

Vinegar and water might not be strong enough. Cats can smell things that people can't. Maybe try a cleaner specially for cat urine/marking.

There is a smell that he is getting that is causing him to continue to mark his territory, see if there is a female cat outside. That could be a main cause. Other than that, you are gonna have to call the vet because as far as i know you have done all you can do!

well I heard that cats hate the smell of citrus, you can get some citrus spray at a pet store. there are all sorts of repellent sprays that you can use around where your cat likes to spray.

I hoped I helped and it doesnt come to you sedating him

All of my cats, male and female spray in my house--they are marking their territory. I have no idea how to make them stop. All of mine are fixed as well, so it's not marking for sexual purposes. I would also appreciate any help in this matter.

have you tried putting a bitter spray on the furniture or wherever he sprays? it will give it a bitter smell and he wont want to mark there. you may want to take him to the vet to ask him/her what you can do about it and get meds if needed