Aims: to compare the efficacy and tolerance of midazolam, 15 mg and zopiclone 7.5 mg once daily for seven days in a prospective, double blind trial of 88 patients, aged 18 or over, with sleep disorders in general practice. Methods: efficacy was evaluated using the Leeds sleep evaluation questionnaire (LSEQ). Adverse reactions were recorded as volunteered. Results: fifty-one patients completed all aspects of the trial without violation of the protocol. Patients taking zopiclone improved in all aspects of the Leeds questionnaire (p < 0.01). Patients taking midazolam improved in six out of 10 items (p < 0.01). Rebound insomnia was evident in the zopiclone group in five out of 10 items of the LSEQ. Rebound was not evident in the midazolam group. There were no significant differences between midazolam 15 mg, and zopiclone 7.5 mg, in comparison between groups. Thirty-eight patients suffered 49 adverse drug reactions and there were no differences between the groups. Conclusions: zopiclone 7.5 mg daily improved more items on the LSEQ than midazolam 15 mg daily but was associated with significant rebound insomnia. Adverse reactions were frequent with both drugs.