An intriguing question is why relatively more people use mental health facilities in one region than in another. Using the Groningen psychiatric case register, admission rates (at least one admission per 1000 of the population during 1986 or 1987) in 34 administrative areas were calculated. Two social indicators (urban/rural and economic status) explained 50% of the variance in the admission rates. Logit models were fitted in order to test the hypothesis that higher admission rates in more urbanized areas are due to the social-demographic composition of the population. It was found, however, that the relative risk for admission is higher in urban areas within all social-demographic subgroups. This finding holds for different diagnostic categories.