The hypnotic efficacy and safety of quazepam 15 mg was compared with placebo in thirty-six out-patients with insomnia. The study was double-blind, with two comparable groups of patients established by random allocation. Following a placebo baseline period, patients took placebo or quazepam for 5 consecutive nights and completed sleep questionnaires the next day. Quazepam was rated better than placebo in terms of sleep quality, sleep induction time, total sleep time, and early morning awakenings. Quazepam treatment was rated as good or excellent by the physician and the patients who received it almost three times more often was placebo. Quazepam was proved to be safe, with no reports of unexpected or serious adverse experiences.