UNLABELLED: CONTEXT. Many health plans have started to cover the cost of complementary and alternative medicine (CAM). National survey data indicate that CAM use is highly prevalent among adults. However, little is known about CAM use among health plan members. OBJECTIVE: To describe CAM users, the prevalence of CAM use, and how CAM use relates to utilization of conventional preventive services and health care satisfaction among health plan members. DESIGN: Cross-sectional mail survey in 1997. SETTING: Managed care organization in Minnesota. SAMPLE: Random sample of health plan members aged 40 and older stratified by number of chronic diseases; 4404 (86%) of the 5107 returned completed questionnaires. MEASURES: Use of CAM, patient characteristics (e.g., chronic diseases, health status), health behaviors (e.g., smoking, diet, exercise), and interaction with conventional health care (e.g., use of preventive services, having a primary care doctor, health care satisfaction). RESULTS: Overall, 42% reported the use of at least one CAM therapy; the most common were relaxation techniques (18%), massage (12%), herbal medicine (10%), and megavitamin therapy (9%). Perceived efficacy of CAM ranged from 76% (hypnosis) to 98% (energy healing). CAM users tended to be female, younger, better educated, and employed. Users of CAM reported more physical and emotional limitations, more pain, and more dysthymia but were not more likely to have a chronic condition. CAM users were slightly more likely to have a primary care provider (86% vs. 82% had chosen a primary care provider; P =0.014) and had more favorable health-related behaviors. CAM users and nonusers were equally likely to use conventional preventive services and were equally satisfied with their health plan. CONCLUSION: CAM use is highly prevalent among health plan members. CAM users report more physical and emotional limitations than do nonusers. CAM does not seem to be a substitute for conventional preventive health care.