A comprehensive population study of women in Gothenburg, Sweden was carried out in 1968-1969. Altogether 800 women participated in the psychiatric study. Four age strata were studied i.e. women born in 1930, 1922, 1918 and 1914. The same women were re-studied in 1974-1975 (participation rate 84.6%) establishing (1) prevalence of mental disorder, (2) six-year incidence of mental disorder, (3) one-year incidence of mental disorder, (4) occurrence of undesirable life events and (5) connections between life events and one-year incidence of mental disorder. The average prevalence rate was 13.4% for mental disorder with functional impairment, exceeded in lower social groups, by the divorced and the recently widowed. Depressive disorders were most common and autonomic disturbances were the most frequent symptoms. The six-year incidence of mental disorder with functional impairment was 19.5% with raised rate for the divorced and the childless. Undesirable life events increased with the number of children, and decreased with age. The one-year incidence rate decreased with increasing age. The one-year incidence of mental disorder was increased with the amount of undesirable life events.