OBJECTIVES: The association between mental distress and health risks, protective health behavior (in the form of preventive health screenings) and health care costs was evaluated among a commercially insured, adult population. METHODS: The sample contains 10,055 employees age 18-75, which is a sub-set of the managed care, health risk assessment database [MCHRA]. The MCHRA data was collected from 2000-2003. Bi-variable analysis, logistic regression and general linear regression models were performed to evaluate the association between mental distress (low, medium and high) and health risks, health lifestyle, preventive health screenings, and health care costs. RESULTS: Using multi-variable logistic regression models, those with high mental distress were significantly more likely to smoke (adjusted odds ratio [AOR] 1.26, p = 0.0027), drink alcohol (AOR 5.75, p <0.0001), more likely to not wear a helmet when biking (AOR, 1.37, p = 0.0188), more likely to be overweight (AOR 1.21, p = 0.0350), more likely to feel a loss of self esteem (AOR 8.86, p <0.0001), more likely to have lost interest in life (AOR 12.23, p <0.0001), more likely to report depression (AOR 16.53, p <0.0001), more likely to have sleep problems (AOR, 3.81, p < .0001) and less likely to be tested for colon cancer through FOBT tests (AOR 1.429, p = .0006) or colonoscopy (AOR 1.93, p <0.0001). Those with mental distress were more likely to have higher health care costs overall (> $1,700; F = 20.08, p <0.0001). Health care cost areas associated with disease classifications showed those with higher distress had higher costs related to treatment of mental disorders (> $140; F = 44.50, p <0 .0001), the nervous system (> $70; F = 3.34, p = 0.0675) and respiratory system (> $120; F = 15.36, p <0.0001). CONCLUSIONS: The findings indicate a strong association between mental distress, health risk and lifestyle, and preventive health behavior and health care costs.