Objective To investigate the effect of ramelteon on sleep and daytime functioning among individuals with traumatic brain injury (TBI). Design A double-blind, placebo-controlled study with a crossover design. Setting A research facility attached to an acute rehabilitation hospital. Participants Individuals with TBI (N=13) complaining of sleep difficulties with a Pittsburgh Sleep Quality Index score >5. Interventions A nightly dosage of ramelteon (8mg) was given over a period of 3 weeks. Main Outcome Measures An actigraph and a daily sleep log were used to measure sleep/wake patterns. Daytime functioning was measured after 3 weeks of treatment using a computer-administrated neuropsychological test battery in conjunction with subjective questionnaires measuring mood, daytime sleepiness, and fatigue. Results A significant increase in objectively measured total sleep time and a small increase in sleep latency were observed after 3 weeks of treatment compared with placebo. Treatment also showed a significant increase in standardized neuropsychological test scores, with a particular improvement on an index of executive functioning. Conclusions Preliminary evidence for the effectiveness of 8mg of ramelteon taken nightly over a 3-week period was found in the treatment of sleep difficulties among individuals with TBI. Improvements in total sleep time and some aspects of cognitive functioning are discussed.