We studied 112 patients with Tourette's syndrome (TS); the male-to-female ratio was 3.8, the mean age of onset was 7.3 years, and the average duration of symptoms prior to the initial evaluation was 15.2 years. Seventy-nine percent of the patients had at least one family member with motor or vocal tics, and an additional 10 percent had a family member with marked obsessive-compulsive behavior. Simple motor tics occurred as the presenting symptom in about one-third of patients; one-third had multiple motor tics at the onset, and another third started with vocal tics. During the course of the illness all patients developed multifocal motor tics and 86 percent had vocal tics. Verbal and mental coprolalia was present in 44 percent of the patients. Copropraxia was seen in 19 percent of patients, and both coprolalia and copropraxia were more frequent among the males than expected. Attentional deficit disorder was diagnosed in 36 percent of the patients and 32 percent had obsessive-compulsive personality. Sleep disturbances were reported by 62 percent of the patients and polysomnographs in 34 patients showed motor and vocal tics during all stage of sleep, sleep apnea, abnormal arousal pattern, and other sleep disturbances. Patients with mild symptoms improved with clonidine or clonazepam, but those with more advanced disorder required fluphenazine, pimozide, haloperidol or tetrabenazine.