Although the Mexican-American elderly represent a large and rapidly growing subgroup of the ethnic aged, national prevalence data of major chronic diseases among this population are sparse. Data based on physical examinations from three older groups of the southwestern portion of the 1982-1984 Hispanic Health and Nutrition Examination Survey (HHANES) were reviewed to determine rates of hypertension, diabetes mellitus, arthritis, and heart disease. The results show a higher prevalence of diabetes and lower prevalence of heart disease and hypertension when compared with the general population, coinciding with data from previous studies. Findings for the prevalence of arthritis varied widely from other studies, however, and proportions were lower than expected. Further research on arthritis in the Mexican-American elderly is necessary to determine whether protective mechanisms that may lead to a lower prevalence of this disease exist in this ethnic subgroup.