Of two large-scale government-commissioned studies of common mental disorders in the UK, one found occupational social class to be the strongest marker of risk while the other showed no clear relationship. This study reviews the published evidence on the links between conventional markers of social position and the common mental disorders in developed countries. Inclusion criteria covered general population based studies with broad social class variation; samples of 3,000 or more adults of working age; identification of mental illness by validated instruments; social position identified by explicit standard markers; fieldwork undertaken since 1980; published output on key areas of interest. Incompatible study methods and concepts made statistical pooling of results invalid. Of nine studies, eight provide evidence of an association between one or more markers of less privileged social position and higher prevalence of common mental disorders. For some individual indicators in particular studies, no clear trend was evident, but no study showed a contrary trend for any indicator. The more consistent associations were with unemployment, less education and low income or material standard of living. Occupational social class was the least consistent marker. Common mental disorders are significantly more frequent in socially disadvantaged populations. More precise indicators of education, employment and material circumstances are better markers of increased rates than occupational social class.