The present study sought to determine gender- and age-specific prevalences of chronic diseases in an urban Mexican American border community. The Cameron County Hispanic Cohort (CCHC; n = 2,000) was selected using a multistaged cluster design. Sociodemographics, anthropometric measures, and blood samples were collected on each participant. More women were obese (55.1%) than men (44.8%). Men had significantly higher rates of diabetes (20.4% for men vs. 15.8% for women, p < .05) and undiagnosed diabetes (6.2% for men vs. 2.4% for women, p < .01); the prevalence of diabetes rose steeply between the ages of 40 and 49 years. Men were significantly more likely to have serum cholesterol levels of 200 mg/dL and elevated low-density lipoprotein levels (22.6% vs. 26.1%, p < .01). Mexican American males in the U.S./Mexico border region have a high prevalence of obesity in younger men and higher overall rates of diabetes, including undiagnosed diabetes, and significantly higher serum cholesterol levels than women.