BACKGROUND: Studies have suggested that social inequalities in chronic disease outcomes differ between industrialized and developing countries, but few have directly compared these effects. We explored inequalities in hypertension and diabetes prevalence between African-descent populations with different levels of educational attainment in Jamaica and in the United States of America (USA), comparing disparities within each location, and between countries. METHODS: We analyzed baseline data from the Jackson Heart Study (JHS) in the USA and Spanish Town Cohort (STC) in Jamaica. Participants reported their highest level of educational attainment, which was categorized as ’less than high school’ (<HS), high school (HS) and ‘more than high school’ (>HS). Educational disparities in the prevalence of hypertension and diabetes were examined using prevalence ratios (PR), controlling for age, sex and body mass index (BMI). RESULTS: Analyses included 7248 participants, 2382 from STC and 4866 from JHS, with mean age of 47 and 54 years, respectively (p < 0.001). Prevalence for both hypertension and diabetes was significantly higher in the JHS compared to STC, 62% vs. 25% (p < 0.001) and 18% vs. 13% (p < 0.001), respectively. In bivariate analyses there were significant disparities by education level for both hypertension and diabetes in both studies; however, after accounting for confounding or interaction by age, sex and BMI these effects were attenuated. For hypertension, after adjusting for age and BMI, a significant education disparity was found only for women in JHS, with PR of 1.10 (95% CI 1.04-1.16) for < HS vs > HS and 1.07 (95% CI 1.01-1.13) for HS vs > HS. For diabetes; when considering age-group and sex specific estimates adjusted for BMI, among men: significant associations were seen only in the 45-59 years age-group in JHS with PR 1.84 (95% CI 1.16-2.91) for < HS vs > HS. Among women, significant PR comparing < HS to > HS was seen for all three age-groups for JHS, but not in STC; PR were 3.95 (95% CI 1.94-8.05), 1.53 (95% CI 1.10-2.11) and 1.32 (95% CI 1.06-1.64) for 25-44, 45-59 and 60-74 age-groups, respectively. CONCLUSION: In Jamaica, educational disparities were largely explained by age, sex and BMI, while in the USA these disparities were larger and persisted after accounting these variables.