Morbid jealousy can occasionally be indistinguishable from obsessive-compulsive neurosis and then be partially amenable to broad-spectrum behavioural treatment. This can involve the partner and includes (a) methods to reduce jealousy and (b) other methods where appropriate, such as social skills training, and sex and marital therapy. This pilot study describes such treatment of four jealous out-patients. Rituals improved in three patients but ruminations in only one. Of three patients who were depressed at the start of treatment, two improved in rituals and in mood. The patient who failed was poorly motivated and did not comply with treatment.