During a double-blind clinical study, a new hypnotic benzodiazepine, lormetazepam (Wy 4082), was compared at a fixed dose of 1 mg to sodium amobarbital at a fixed dose of 100 mg for the treatment of moderate insomnia in 2 groups of 25 psychiatric outpatients. The medication was given at bedtime and the duration of the study was limited to 2 weeks. The quality of sleep was evaluated by the patient after the first night and at the end of the first and second week and by investigator at the end of the 2 weeks trial. The two products appeared effective on global assessment, but with an advantage in favour of lormetazepam: earlier onset of sleep and excellent acceptability on the final evaluation. Fifty two per cent of patients treated with amobarbital had side effects, mainly hangover and sedation during the morning, while only one patient treated with lormetazepam complained of headaches in the morning.