The aim of this study is to evaluate the efficiency of a treatment prescribed, in the course of an hospital consultation for sleep pathology, to patients suffering from chronic insomnia not improved by longstanding and sustained medication with hypnotic drugs. The basis of the treatment is a progressive but total withdrawal of hypnotics in so far taken regularly. The withdrawal of hypnotics was prescribed to 79 patients: 33 aged 17 to 39 years (group 1, mean age 30) and 46 aged 40 to 70 years (group 2, mean age 51). 41 showed primary psychophysiological insomnia and 28 showed insomnia associated with psychiatric disorders. In patients of group 1, the average durations were 8 years for insomnia and 3 years for sustained hypnotic use; these durations were 15 and 5 years respectively in patients of group 2. Hypnotic drug withdrawal was achieved without placebos in 3 months in group 1 patients and 5 months in group 2 patients. 65 patients completely stopped the continual use of hypnotics. Subjective improvement of insomnia was reported by 51 of these patients (as well as by 6 patients who were given simultaneous antidepressant therapy). 16 of the 51 improved patients have resorted to hypnotics occasionally (at intervals of 10 days or more). After complete withdrawal, patients went on consulting for various lengths of time: 5 months average for group 1, 14 months average for group 2. This study of a fairly large group of insomniacs shows the frequent ineffectiveness of a sustained use of currently available hypnotics. It also shows that two times out of three the complete stop of sustained hypnotic medication proved beneficial to the patient.