Information about all admissions to psychiatric hospitals and departments in Denmark in 1977, 1982 and 1987 and about all resident patients on census days in the same years were extracted from the central psychiatric register. The number of available beds decreased by 43% from 1977 to 1987. The admission rates decreased for all diagnostic groups but schizophrenia, which increased. The group of younger schizophrenic men declined in size, which is alarming if mentally ill homeless people are considered. The census study shows a decrease in all diagnostic groups, most pronounced in the elderly age groups. Patients with neuroses disappear from the available beds in the mental hospitals and departments. The changes in the psychiatric service system from mostly hospitalization to outpatient treatment and community psychiatric treatment require a comprehensive personal registration of treatment regardless of the administrative affiliations of these services.