This study investigated the functional impairment (work and social functioning and general health status) associated with migraine and tension-type headache (TTH) among young adult members of the Dunedin Multidisciplinary Health and Development Study. Using criteria based on the International Headache Society classificatory system, the 1-year prevalence for migraine headache was 7.4%, TTH was 11.1%, and combined headache (coexisting migraine and TTH) was 4.3%. All comparisons were against a health control group (headache free) and a diagnostic control group (individuals without headache currently using medication for asthma). Although those suffering from migraine and combined headache had the most severe impairment in work- and social-related activities, those with TTH reported significantly poorer social and mental health functioning and poorer emotional and physical functioning while performing everyday roles than did headache-free controls. Study members with combined headache had the poorest self-reported health, with significantly lower ratings on physical, vitality, and mental health measures than asthmatics currently using medication. The pervasive impairment reported across multiple life domains among young headache sufferers illustrates the significant burden of illness associated with headache disorders.