OBJECTIVE: Major mental disorders occur more frequently in deprived urban areas. This study examines whether this occurs for all mental disorders, including less serious ones. It further assesses whether such a concentration can be explained by the socioeconomic status (SES) of the residents concerned or that a cumulation of problems in deprived areas reinforces their occurrence. DESIGN: Mental disorders were assessed by means of the General Health Questionnaire (GHQ) among 4892 residents. Additional data were obtained on area deprivation, and on individual SES. Multilevel logistic regression models were used to take the hierarchical structure of the data into account, residents being nested in boroughs. SETTING: General population of the city of Amsterdam, the Netherlands. MAIN OUTCOME MEASURE: Prevalence of an increased (> or = 2) score on the GHQ, 12 item version. RESULTS: Mental disorders occur more frequently in deprived areas but this can be explained by the lower SES of the residents concerned. CONCLUSIONS: The cumulation of mental disorders in deprived urban areas is mainly a result of a concentration of low SES people in these areas. Contextual factors of deprived urban areas give hardly any additional risk above that resulting from a low individual SES.