It may seem like neutering a cat opens up a magic world of possibilities, one where your pet is healthier, is more relaxed and never sprays or has potty issues. Unfortunately, as great as those things all sound, they aren't necessarily always true. Urinary woes are possible in all kitties.
One common -- and very icky -- urinary problem in cats is urine marking. Neutering a male cat usually eliminates or at least greatly reduces urine-spraying behaviors. After all, once a tomcat is no longer driven by hormones, he essentially loses the desire to alert females of his mating availability -- and the desire to get yucky urine all over your favorite sofa. Some cats do retain the pesky but natural behavior after neutering, especially if their owners waited a long time to get the surgery done. For some felines, urine spraying becomes a habit, with or without mating desires.
If your cat is ignoring his litter box in favor of your wallpaper, the urinary nightmare could be related to territorial competition. For example, if you recently introduced a brand new fluffy addition into your home, your neutered cat may be feeling a little threatened by the new blood. Spraying urine is a way to mark turf and to show the new guy exactly who is in charge. In these instances, your cat isn't exactly having urinary problems. He knows exactly what he's doing and exactly what message he is trying to get across to his new household "threat."
Anxiety and Stress
Stress could be causing your little fluff ball to relieve himself everywhere but in his appropriate box. One of the main sources of feline stress is major change, whether you moved into a smaller apartment across time or are in the midst of a messy divorce with your spouse. When a cat is nervous, stressed out and uncertain about his surroundings, it can lead to litter box "amnesia." If you notice your precious pet going No. 1 in the most inconvenient of spots, instead of scolding him, figure out what you can do to ease his anxiety, instead.
Urinary problems aren't always a result of stress or natural instinctive feline behavior. Sometimes, urinary problems are a sign that your cat may be suffering from a medical issue; think urinary tract infection. If your neutered pet has a UTI, you may notice unusual symptoms such as incontinence due to bladder dysfunction or even increased thirst. If you suspect that this may be the case with your cat, schedule an appointment with the veterinarian as soon as possible. Other potentially health-related causes of urinary problems include kidney failure, liver disease, bacterial bladder infection and diabetes. Your pet is worth it, so waste no time in getting him to the vet.