All patients who were first-admitted to Danish psychiatric institutions in the calendar years 1970, 1973, 1976, 1979, and 1982 and who were diagnosed as schizophrenics at least once within a 2-year period of observation from the first day of the first admission are followed up by means of the nation-wide Danish Psychiatric Register (totally 1,175 males and 665 females). Sex and age specific first-admission rates of schizophrenia show that the difference between male and female rates especially appears in the age group 15-24 years. In this age group the peak incidence is found for both sexes, also if the patients only diagnosed as schizophrenics at a later admission are included. The ratio of male to female incidence rates are not changed by inclusion of the latter patients. A higher frequency of married or formerly married patients is found among the schizophrenics who were diagnosed late in the course of treatment than among those who were so at first-admission. This might be a manifestation of a less severe symptomatology which could explain the tendency to hesitate in diagnosing patients as schizophrenics.