In a representative study of 5356 five-year-old children, 4405 (82.2%) could be traced for follow-up. Headache occurred in 861 (19.5%) of them; highly frequently in 0.2%, fairly frequently in 0.5%, less frequently in 4.3% and infrequently in 14.5%. Type of dwelling was the only predictor of housing standard, the risk of headache being about 1.5-fold in children living in other than one-family houses. Low economic status of the family, nursery day care and an increasing number of leisure activities were additional risk factors. Compared with infrequent or no headache, those with highly frequent or fairly frequent headache were at a 1.4-fold risk of temper tantrums. The risk of stomach ache was 8.9-fold in children with infrequent headache and 13.7-fold in those with fairly frequent or frequent headache compared with children with no headache.