A questionnaire study on pre-pregnancy headache and its predictors was carried out in a representative sample of young adults expecting their first baby. The study was part of a major project on the competence of Finnish families. It included 1322 women and 1257 men, either married or cohabiting (in total, 1262 families), followed from their first contact with a maternity health care unit. A questionnaire was given separately to the women and men inquiring about their health and health behaviour, as well as about sociodemographic and psychosocial factors. The prevalence of frequent headache (at least one episode per month) was 34.3% in women, 19.3% in men and 47.1% in families. On multivariate analysis, after age-adjustment, the independent predictors of headache occurrence in women were depression, menstrual pain, responsibilities at work and psychosocial stress. The predictors in men were nervousness, psychosocial stress, lack of or irregular physical exercise and long-term disease, depression, responsibilities at work and insomnia.