This study concentrates on the relationship between urbanisation and incidence of psychiatric admissions. For 1991 the level of urbanisation for all Dutch municipalities and the incidence of psychiatric admissions to a General Psychiatric Hospital, a Psychiatric Unit of a General Hospital or a Psychiatric Unit of a University were determined. Almost 40% of the Dutch population lives in 56 municipalities which are highly or extremely highly urbanized and this group of municipalities accounts for approximately 54% of the psychiatric admissions in a General Psychiatric Hospital. In the 12 largest cities of the Netherlands, almost twice as many psychiatric patients per 1,000 inhabitants were admitted to a General Psychiatric Hospital than in the 313 non-urban municipalities. These higher incidences were not found for the admissions to a Psychiatric Unit of a General Hospital or a Psychiatric Unit of a University. The principal finding is that the higher the degree of urbanisation in a municipality, the higher the total admission incidence. Further research will have to examine the role of socio-economic status in the development of psychiatric disturbances.