Incompetence of the urethral sphincter mechanism is uncommon in male dogs. This paper reviews 54 cases. As in the bitch, the condition can occur either as a congenital or as an acquired condition, in which neutering may play a part; larger breeds appear to be at greater risk. Incontinence is more likely to occur when the intra-abdominal pressure might be expected to increase, for example when the dog is recumbent. In comparison with the bitch, the condition appears less likely to respond to medical therapy and its pathophysiology is poorly understood.