To document the health resource utilization of patients who repeatedly use emergency department services for headache care. Patients with headache who frequently use emergency department services may differ from patients with more typical, episodic migraine. Previous studies of health resource utilization have often failed to distinguish the high utilizer as a specific subset of the migraine population. Retrospective review of urgent care/emergency department charts, clinic charts, and pharmacy rosters. Patients who made three or more visits for headache to an urgent care/emergency department (UC/ED) facility for headache over a 6-month study period were identified and designated as "repeaters" for this study. Pharmacy profiles and appointment histories of 52 of the 54 repeaters whose records were available were reviewed for the 12 months prior to the study period. Over the 6-month study period, 518 patients visited the UC/ED 1004 times for primary headache complaints. Fifty-four (10%) repeaters made 502 visits (50% of total visits; mean 9.3, range 3-50). In the 12 months prior to the study period, 52 of these repeaters made 1832 visits to the UC/ED or clinic (mean 35.2, range 0-178): 1458 (79.6%) were headache related, and 1271 (69.4%) of all visits were to the UC/ED. An estimated 12-month cost for all visits was $183,760. Pharmacy rosters showed use of narcotics in 41 of the 52 patients (annual mean +/- SD, 613 +/- 670 tablets), benzodiazepines in 30 patients (500 +/- 486 tablets), and butalbital products in 27 patients (395 +/- 590 tablets). Mean daily use of all symptomatic medications combined was 3.9 +/- 3.2 doses/day. Health resource utilization of emergency department headache repeaters is predominantly headache-related acute care. Associated medication overuse is frequently present. Efforts to improve care for patients with headache will benefit from distinguishing the high utilizer as a subset of the migraine population.