This chapter discusses the post-traumatic sleep-wake disturbances and post-traumatic sleepiness. Two prospective studies on post-traumatic sleep-wake disturbances identified excessive daytime sleepiness (EDS) as the most common symptom after traumatic brain injury (TBI), but other symptoms also frequently occur. A study found sleep-wake disturbances in 46% of the examined population, with post-traumatic sleepiness as the most common finding. TBI patients often ask their doctors whether or not their enhanced sleep drive and their increased sleep need will ameliorate over time. The interview and scales should consist not only of sleepiness questions, but should also include questions on fatigue and hypersomnia, because these symptoms may be related. Sleep-wake disturbances likely result from and contribute to multiple factors associated with the brain injury, all of which complicate recovery and resolution of symptoms. To create evidence, larger multicenter trials are currently being undertaken to study the effect of modafinil and armodafinil on post-traumatic sleepiness.