The relationship between changes in individual behavior and arterial blood pressure was studied in a town in central Mexico. Two models relating modern behaviors and blood pressure were examined. The first, or 'accretion model' suggests that any adoption of modern behaviors results in stress and deleterious health change. The second, or 'discrepancy model', suggests that the adoption of modern behaviors is problematic only when the individual has limited access to economic resources. Empirical support for both models was found, but the best predictor of blood pressure was a single index of modern lifestyle, including acquisition of material culture and engaging in cosmopolitan behaviors. The effect of modern lifestyle on blood pressure was independent of the effects of age, sex, sodium intake, and body mass index. Overall the results are consistent with a model in which degree of community modernization, especially as it influences social class structure, is a boundary condition determining the relationship between the adoption of modern behaviors and health status.