BACKGROUND: Chronic sleep-onset insomnia is a prevalent health complaint in adults. Although behavioral and pharmacological therapies have been shown to be effective for insomnia, no placebo-controlled trials have evaluated their separate and combined effects for sleep-onset insomnia. The objective of this study was to evaluate the clinical efficacy of behavioral and pharmacological therapy, singly and in combination, for chronic sleep-onset insomnia. METHODS: This was a randomized, placebo-controlled clinical trial that involved 63 young and middle-aged adults with chronic sleep-onset insomnia. Interventions included cognitive behavior therapy (CBT), pharmacotherapy, or combination therapy compared with placebo. The main outcome measures were sleep-onset latency as measured by sleep diaries; secondary measures included sleep diary measures of sleep efficiency and total sleep time, objective measures of sleep variables (Nightcap sleep monitor recorder), and measures of daytime functioning. RESULTS: In most measures, CBT was the most sleep effective intervention; it produced the greatest changes in sleep-onset latency and sleep efficiency, yielded the largest number of normal sleepers after treatment, and maintained therapeutic gains at long-term follow-up. The combined treatment provided no advantage over CBT alone, whereas pharmacotherapy produced only moderate improvements during drug administration and returned measures toward baseline after drug use discontinuation. CONCLUSIONS: These findings suggest that young and middle-age patients with sleep-onset insomnia can derive significantly greater benefit from CBT than pharmacotherapy and that CBT should be considered a first-line intervention for chronic insomnia. Increased recognition of the efficacy of CBT and more widespread recommendations for its use could improve the quality of life of a large numbers of patients with insomnia.