The risk of death in people with epilepsy is increased because of disorders that cause epilepsy, known consequences of seizures, and SUDEP (sudden unexplained death in epilepsy). The incidence of sudden death is many times higher in an epilepsy population than for the general public. SUDEP risk increases with the severity of epilepsy but paradoxically affects young adults preferentially. Important risk factors for SUDEP include age 15 to 45 years, refractory epilepsy, tonic-clonic seizures, nocturnal seizures, and periods during which the patient is not observed. Analyses of epidemiologic studies, observations from witnessed near-deaths or deaths, and pathology data have helped focus attention on respiratory and cardiovascular dysfunction as potential mechanisms of SUDEP. Ictal and postictal effects on autonomic functioning and accidental suffocation are commonly cited as potential factors. Monitoring of patients with a history of nocturnal tonic-clonic seizures might help prevent SUDEP.