Six-month prevalence rates for selected DSM-III psychiatric disorders are reported based on community surveys in New Haven, Conn, Baltimore, and St Louis. As part of the Epidemiologic Catchment Area program, data were gathered on more than 9,000 adults, employing the Diagnostic Interview Schedule to collect information to make a diagnosis. The most common disorders found were phobias, alcohol abuse and/or dependence, dysthymia, and major depression. The most common diagnoses for women were phobias and major depression, whereas for men, the most predominant disorder was alcohol abuse and/or dependence. Rates of psychiatric disorders dropped sharply after age 45 years.