Twenty-four volunteers (19 women and five men) with insomnia and a history of chronic use of benzodiazepine hypnotics participated in a randomized, double blind, controlled clinical trial. The study was designed to assess the effects of substituting zopiclone (ZOP)- as an hypnotic- among chronic users of flunitrazepam (FLU), and to compare the subsequent withdrawal of ZOP with placebo controlled withdrawal of FLU. During the 5 weeks of a withdrawal protocol, sleep and physiological parameters were assessed by polysomnographic measures for 11 nights and by nightly actigraphic recordings for weeks 1, 3, and 5. Subjective effects of the withdrawal process were evaluated with daily sleep diaries, and with various weekly self-report symptom checklists. Paired t-tests performed on differences in objective sleep parameters between baseline and the last weeks of the withdrawal program showed a significant decrease in sleep quality within the FLU group, but not in the ZOP group. Subjective sleep diaries consistently reflected the objectively measured changes in sleep throughout the withdrawal program, indicating significant changes in sleep parameters only in the FLU group. The results obtained from the self report inventories aimed at assessing withdrawal symptoms, however, revealed no differences between the baseline week and the termination week of the program in any of the groups. After completing the pharmacological withdrawal, all subjects received a short-term cognitive behavioral intervention focused on improving their coping strategies with symptoms of insomnia; they were evaluated immediately after concluding the intervention, and at 3 and 12 month follow- ups.