• The reliability and validity of the Psychiatric Epidemiology Research Interview (PERI) are examined using data from a triethnic (white, black, and Mexican-American) sample of community respondents. The PERI scales attempt to measure both nonspecific psychological distress and different dimensions of psychopathology. Internal consistency reliability is assessed using Cronbach's coefficient a. Concurrent and discriminant validity are evaluated by comparing the PERI scales with the Center for Epidemiologic Studies Depression Scale and the Bradburn Negative Affect Scale. These scales show high internal consistency reliability in all three ethnic groups. The Demoralization Scale measures a separate dimension from the other psychopathology scales, and the latter scales are distinct from one another. While the criterion validity of the PERI in population samples remains unknown, it is possible to measure important dimensions of psychopathology in the general population. The PERI may constitute one such measure.