The prevalence of clinical gallbladder disease was determined in a cross-sectional survey of Mexican Americans and non-Hispanic whites. The study population was randomly selected from three urban neighborhoods representing different socioeconomic strata. Gallbladder disease was defined as a history of cholecystectomy, or of stones on cholecystography. Mexican American women had an age-standardized prevalence of 16.9%, vs 8.7% for non-Hispanic whites (p less than 0.0001). Prevalences in men were 4.2 and 3.4%, respectively. The ethnic differences in women persisted after stratification by age, parity, and body mass index. Gallbladder disease prevalence was inversely related to four measures of socioeconomic status. After controlling for age, obesity, parity, and ethnicity, the prevalence in women was inversely related to levels of education, income, occupational status, and neighborhood. These socioeconomic differences, if not the result of detection bias, suggest that environmental factors may play a role in gallstone pathogenesis. Identification of such factors may lead to the development of preventive strategies.