Somatization disorder, the presentation of multiple somatic complaints in multiple organ systems, can be diagnosed by three roughly comparable diagnostic systems: the Washington University Feighner criteria, the Research Diagnostic Criteria, and DSM-III criteria. This study evaluates diagnostic concordance for somatization disorder in these three diagnostic systems using data gathered in the National Institute of Mental Health-sponsored Epidemiologic Catchment Area Program at four sites. Data gathered through use of the Diagnostic Interview Schedule at the Duke, Johns Hopkins, Washington, and Yale University sites indicate that each criterion set identifies a somewhat different group of respondents. Feighner criteria identify the fewest number of respondents, followed by DSM-III criteria and the Research Diagnostic Criteria. Demographic, symptomatic, health utilization, and other severity indices indicate that the respondents identified by each group are very similar and that all diagnostic groups are clearly distinguishable from the normal population.