Alcohol detoxification is accompanied by sustained difficulties in sleep initiation and maintenance. These difficulties are thought to be an important cause of relapse to alcohol use. However, the treatment of sleep problems with hypnotic drug is made difficult by cross-tolerance between benzodiazepines and alcohol. In this report, we evaluated the capacity of trazodone (TRZ), a second-generation antidepressant with anxiolytic and sedative properties, to increase the sleep efficiency in alcohol-dependent patients after detoxification. Sixteen patients completed the TRZ (n = 8) or the placebo (PL; n = 8) treatment arms. Polysomnographies were performed at baseline, after the 1st drug dose, and after 4 weeks of treatment. The main outcome was sleep efficiency. Secondary outcomes included changes in other sleep parameters, Hamilton Depression Rating and Clinical Global Impression scales. Sleep efficiency was increased in the TRZ group when it was computed after sleep onset, both immediately after 1st administration of the drug and after 4 weeks of treatment. No benefit was observed in the PL group. Sleep improvement under TRZ also included the number of awakenings, intermittent wake sleep time, and non—rapid eye movement sleep. Hamilton and Clinical Global scales were better for the TRZ group. TRZ is thus a potential option in the treatment of alcohol post-withdrawal insomnia.