The aim of this study was to find the prevalence of migraine and headache in schoolchildren in the United Arab Emirates and to determine the genetic and environmental factors associated with these conditions. A cross-sectional population study was performed from October 1995 to June 1996. Subjects were selected by a multistage stratified sampling procedure. Data were collected by screening questionnaires followed by clinical interviews. Twelve primary schools and 1400 schoolchildren of United Arab Emirates nationality resident in the Al Ain City, Dubai, and Sharjah emirates were recruited for this study. A total of 1159 (82.7%) schoolchildren gave their consent to the study. The estimated prevalence rates for headache and migraine were 36.9% and 13.7%, respectively. The prevalence of headache is increased with age, the highest prevalence being in 13-year-old children (17.5%). Of the 159 children who fulfilled the diagnostic criteria for migraine, 76 were boys whose mean age (+/- SD) was 10.3 years +/- 2. 8 years, and 83 were girls (mean age 9.9 +/- 2.5 years). Of the children who had migraine, 20 (12.6%) had migraine without aura, and 13 (8.2%) had migraine with aura. The most common migraine symptoms in schoolchildren had been aggravated by physical activity (47.2%) and a positive family history of migraine (46.5%). The most common illnesses were infectious illnesses (41.5%). There was a strong relationship between migraine and the timing of examinations (46.5%). The most common environmental exposure for migraine was found to be playing on a computer (45.9%), followed by loud noise (41.5%), and a hot climate (37.1%). In familial occurrence of headache among immediate relatives, the most frequently affected relative was the mother (17.6%). .-Headache and migraine are common in childhood and may be influenced by social, familial, environmental, and psychological factors.