Self-efficacy has a well-established, beneficial effect on health behavior and health status in young and middle-aged adults, but little is known about these relationships in older populations. We examined this issue as part of a randomized trial to determine the cost savings and changes in health-related quality of life associated with the provision and reimbursement of a preventive services package to 2,524 Medicare beneficiaries enrolled in Group Health Cooperative of Puget Sound. Baseline self-efficacy data were collected for all participants in five behavioral areas: exercise, dietary fat intake, weight control, alcohol intake, and smoking. Results reveal that efficacy and outcome expectations for these health behaviors are not independent. Correlational and factor analyses indicate two dimensions of efficacy expectations, one consisting of exercise, dietary fat, and weight control, and another consisting of smoking and alcohol consumption. Outcome expectations of the five behaviors form a single dimension. Older adults with high self-efficacy had lower health risk in all behaviors and better health. Regression analyses detected a positive association between socioeconomic status and health-related quality of life (p < .02), but the strength of the association declined (p < .11) after the self-efficacy measures entered the model, indicating that self-efficacy explains part of the association between socioeconomic status and health status. Interventions aimed at improving self-efficacy also may improve health status.