The comparative measurement performance of self-reported health status instruments for African American and Hispanic elderly has rarely been studied, despite evidence of their poor health status. This study examined psychometric performance and health status differences by age, ethnicity, and gender among 10,569 ethnically diverse patients who completed the Short-Form General Health Survey in the Medical Outcomes Study (MOS). Hispanics and African Americans tended to have slightly lower measurement performance than other ethnic groups. Compared with whites, health status scores for African American and Hispanic women were slightly but significantly lower. The small differences in health status by ethnicity may be due to the MOS sampling strategy, which excluded low-socioeconomic status minorities with poor education and no regular medical care. The psychometric performance of MOS health status measures should be examined in studies of ethnically diverse, community-dwelling, elderly populations who have poor access to care, poor education, and/or low socioeconomic status.