Before they're neutered, male cats use urine marking primarily to attract a mate. Having your cat fixed isn't a guarantee that the marking will stop. Even after they are neutered, male cats may go on marking, creating unpleasant stains and smells throughout your home. If you can identify the possible cause of his behavior, you can seek treatment advice from a veterinarian or behaviorist.
Old habits die hard, especially in pets. The longer a cat keeps up a habit such as urine marking, the harder it is to break, even after neutering curbs his hormonal motivation to do so. Ideally, a cat should be neutered by the age of 5 months, before urine marking becomes a habit. If you neuter an older cat, he may not quit spraying. If your cat continues to spray, seek help from a professional trainer.
Stress compels even neutered cats to urine mark, and these creatures of habit are stressed out by change. Sudden changes like moving or bringing home a new baby can give your cat stress, which may manifest in loss of appetite, aggressive behavior or marking his territory.
Conflict with another cat also can compel your neutered pet to spray out of fear and anxiety. The stress caused by conflict, be it fighting, bullying or even the presence of an outside cat visible through the window, may compel your cat to spray. A behaviorist specializing in socialization may be able to help.
Unfortunately, some cats simply are prone to high anxiety. This can be caused by things such as a history of abuse or a neurological disorder. That natural state of stress can drive him to urine mark even after being neutered. Because his anxiety comes from within, and not necessarily from an external factor, consult with your veterinarian. Some cats benefit from prescription medications that calm their nerves, allowing them to relax.