Objective: Reviews of urban-rural differences in psychiatric disorders conclude that urban rates may be marginally higher and, specifically, somewhat higher for depression. However, pooled results are not available. Method: A meta-analysis of urban-rural differences in prevalence was conducted on data taken from 20 population survey studies published since 1985. Pooled urban-rural odds ratios (OR) were calculated for the total prevalence of psychiatric disorders, and specifically for mood, anxiety and substance use disorders. Results: Significant pooled urban-rural OR were found for the total prevalence of psychiatric disorders, and for mood disorders and anxiety disorders. No significant association with urbanization was found for substance use disorders. Adjustment for various confounders had a limited impact on the urban-rural OR. Conclusion: Urbanization may be taken into account in the allocation of mental health services. © 2009 John Wiley & Sons A/S.