1 The efficacy of flurazepam (15 mg or 30 mg) as a hypnotic, and the residual effects of each dose were compared with placebo in a double-blind cross-over trial involving thirty patients in a general practice setting. Patients received each medication for one week. Daily self-ratings of onset, duration and quality of sleep, together with reports of any untoward effects were made. At the end of each period of medication psychomotor tests (reaction time, pursuit rotor, tapping speed) were administered at 09.00 hours. 2 Both doses of flurazepam were significantly more effective than placebo in inducing sleep, improving the quality of sleep and extending its duration. 3 'Hangover' effects were marked following 30 mg, but not after flurazepam (15 mg). Flurazepam (30 mg, but not 15 mg) significantly impaired performance on the pursuit rotor test and tapping speed. Flurazepam thus appears to be an effective hypnotic drug with the optimum dose for use in general practice being 15 mg at night.