A representative epidemiological study on the occurrence of migraine and other headaches in Finnish schoolchildren 14 years of age is presented. The investigation covered 3863 pupils, accounting for 94.2% of the total of 4101 mentally normal children, who went to school in two big Finnish cities. There were 1954 boys and 1909 girls in the study. They were given a one-page questionnaire with four questions concerning the frequency and the nature of headache in themselves and their family members. Considerable attention was paid to the wording and unambiguity of each question. The forms were filled in under the control of the home-room teacher, whose check-up of the answers was intended to remove discrepancies between the filled-in forms and the children's complaints. For the clinically working physician, especially the general practitioner, it is worthwhile noticing that during the last 12 months not less than 68% of the 14-year-old schoolchildren had suffered from headache. Headache had been less frequent in the boys (65%) than in the girls (71%). In 10.2% of the schoolchildren migraine attacks had occurred. Again, the boys had migraine less frequently (6.7%) than the girls (13.8%). The combination of individual migraine factors, which occurred in one third of the cases, was unilateral pain and migraine in other family members. The figures are similar to those in another investigation of headaches in schoolchildren.