Separation anxiety is a common behavioral problem in dogs. Treatment is based on developing a behavior modification protocol that gradually desensitizes and counter-conditions the dog to being left alone, by rewarding calm, relaxed behavior (Lem 2002) the presenting complaints varied. These are included: inappropriate urination, excessive vocalization, fearful behavior, trembling, vomiting, diarrhea, excessive licking, self-mutilation, overactive greetings, excessive attention seeking, and aggression at departures (Beaver 1999). This article descries a case of genital self-mutilation as an unusual clinical manifestation of separation anxiety, and is, to the author's knowledge, the first such case reported in veterinary medicine. A two-year old sexually intact male cross-bred dog was presented for evaluation of hemorrhagic preputial discharge. The owner had noted excessive vocalization and intermittent episodes of licking of the penis, when it left alone. The owner had reported that he had a car accident and hospitalized, so he had no chance to meet the dog. During this time, the behavior then would progress to frequent episodes of licking and biting of the penis. The dog lick, bite and severely self-mutilate his penis resulting in ulcers with secondary bacterial infection. Three weeks of treatment with Amitriptyline appeared to produce a considerable degree of improvement. Episodes of biting behavior were reduced and wounds healed gradually. Owner-recorded audiotape tried concomitant to Amitriptyline therapy in the first week of treatment. In the second week after beginning of treatment the dogs brother who kept in another apartment, had brought to the dogs living place. It seemed to be more effective and reported behavior occurred less than first week of treatment.