BACKGROUND: Historically, marital status has been associated with lower mortality and transitions into marriage were generally accompanied by improved health status. Conversely, divorce has been associated with increased mortality, possibly mediated by changes in health behaviors. METHODS: This study uses data from a prospective cohort of 79,094 postmenopausal women participating in the Women's Health Initiative Observational Study (WHI-OS) to examine the relationship between marital transition and health indicators (blood pressure, waist circumference, body mass index [BMI]) as well as health behaviors (diet pattern, alcohol use, physical activity, and smoking) in a sample of relatively healthy and employed women. Linear and logistic regression modeling were used to test associations, controlling for confounding factors. RESULTS: Women's transitions into marriage/marriage-like relationship after menopause were associated with greater increase in BMI (β = 0.22; confidence interval (95% CI), 0.11-0.33) and alcohol intake (β = 0.08; 95% CI, 0.04-0.11) relative to remaining unmarried. Divorce/separation was associated with a reduction in BMI and waist circumference, changes that were accompanied by improvements in diet quality (β = 0.78, 95% CI, 0.10-1.47) and physical activity (β = 0.98, 95% CI, 0.12-1.85), relative to women who remained married. CONCLUSION: Contrary to earlier literature, these findings among well-educated, predominantly non-Hispanic white women suggest that marital transitions after menopause are accompanied by modifiable health outcomes/behaviors that are more favorable for women experiencing divorce/separation than those entering a new marriage.