6 months after traumatic brain injury (TBI), almost three out of four patients suffer from sleep-wake disturbances (SWD) such as post-traumatic hypersomnia (increased sleep need of ≥2 h compared with before injury), excessive daytime sleepiness (EDS), fatigue and insomnia. The long-term course of post-traumatic SWD, however, is unknown. To assess the prevalence and characteristics of post-traumatic SWD 3 years after trauma. Prospective longitudinal clinical study in 51 consecutive TBI patients (43 males, eight females, mean age 40±16 years). EDS (as assessed by the Epworth sleepiness scale), fatigue (fatigue severity scale), post-traumatic hypersomnia (sleep length per 24 h), insomnia, depression and anxiety. Post-traumatic SWD were found in 34 patients (67%): post-traumatic hypersomnia in 14 (27%), EDS in six (12%), fatigue in 18 patients (35%) and insomnia in five patients (10%). SWD were not associated with severity or localisation of, or time interval since, TBI. Insomnia was linked to depressive symptoms. This prospective study shows that 3 years after TBI, two out of three patients suffer from residual SWD, particularly fatigue and post-traumatic hypersomnia. In 45% of TBI patients, SWD appear directly related to the trauma itself.