Sixty-two elderly in-patients suffering from insomnia were studied in a double-blind, double-dummy, placebo-controlled trial. Each group received either lormetazepam 1 mg, chlormethiazole 384 mg or placebo for 7 nights. Both lormetazepam and chlormethiazole significantly increased sleep duration, reduced sleep latency and improved quality of sleep and feelings on awakening. For both drugs, reaction times the next morning were unimpaired and there was no clinical evidence of accumulation after 7 nights continuous dosing. Lormetazepam and chlormethiazole in these doses are effective and safe hypnotics for frail elderly patients.