The associations between the one-month prevalence rates of mental disorders and sociodemographic characteristics were investigated for 18,571 people interviewed in the first-wave community samples of all 5 sites in the US National Institute of Mental Health (NIMH) Epidemiologic Catchment Area program. Men were found to have a significantly higher rate of cognitive impairment than women after controlling for the effects of age, race or ethnicity, marital status and socioeconomic status. Marital status was one of the most powerful correlates of mental disorder risk: the odds of separated or divorced people having any NIMH Diagnostic Interview Schedule disorder were twice that of married people after controlling for age, gender, race or ethnicity and socioeconomic status. The odds of those in the lowest socioeconomic status group having any Diagnostic Interview Schedule disorder was about 2.5 times that of those in the highest socioeconomic status group, controlling for age, gender, race or ethnicity and marital status. For all disorders except cognitive impairment, race or ethnicity did not remain statistically significant after controlling for age, gender, marital status and socioeconomic status.