Technical Abstract: This research examined whether the migration history of overweight Mexican-American women had an independent effect on cardiovascular risk factors, or whether it was mediated by health behavior changes. Cross-sectional data from 390 overweight, non-diabetic Mexican-American women (aged 18 to 65 years), all recruited from Starr County, Texas, were used for this analysis. Migration history was inferred from birthplaces of subjects and relatives, and length of residence in the United States. Health behaviors included tobacco and alcohol use, sleeping, exercise, and dietary practices. The cardiovascular disease risk factor variables (CDRFVs) studied were plasma glucose, abdominal obesity, blood pressures, and blood lipids. A migration history score (MHS) was developed from factor analysis, almost equally contributed to by the 9 migration history variables. Healthy habits were defined by 6 variables, and 3 factors (blood pressures, lipids/glucose, and body fat/glucose) were used for the CDRFVs. MHS was correlated positively with socioeconomic status, and negatively with family stress. Older women had healthier drinking and sleeping habits. Women with a higher migration history score exhibited poorer exercise habits, and increased blood pressures. After adjusting for the effect of healthy exercise habits on blood pressures, the impact of migration history on blood pressures became non-significant (P>.05), leading to the conclusion that healthy exercise behaviors mediated the negative relationship of MHS with blood pressures. Age was independently positively correlated with all CDRFVs. Age also weakly moderated the negative relationship of MHS and healthy exercise habits.