A self-administered questionnaire covering the diagnostic criteria of the International Headache Society was completed by 1208 undergraduates of the National University of Singapore to determine the prevalence and characteristics of headaches in this population. The relationship between headaches and depressive illness was investigated with the Zung Self-assessed Depression Scale. The mean age of respondents was 20.9 +/- 1.6 years; 50.3% were men and 46.4%, women. Ten point nine percent had migraine without aura, 29.8% had tension-type headaches, 1.1% had headaches consistent with migraines with aura, and in 56.3% the headaches could not be classified. The lifetime prevalence of headache in this population was 98.1%. Significantly higher mean Zung scores were found in subjects who had more intense and frequent headaches than in those without headaches and less severe symptoms, although the clinical relevance of this finding is uncertain. Zung scores did not differ significantly with diagnostic group, sex, or race.