The Behavioral Risk Factor Surveillance System (BRFSS) was used to estimate the prevalence of complementary and alternative medicine (CAM). The BRFSS is an annual population-based survey that provides timely, state-specific estimates of risk factors and healthful behaviors related to the leading causes of morbidity and mortality. The BRSS was adapted and used to assess the use of 11 specific types or groups of CAM therapies by Michigan residents in the previous 12 months. The results suggested that 49.7% of Michigan adults had used at least one CAM therapy in the previous 12 months. The most frequently used therapies were herbal supplements, special diets, chiropractic therapy, and other non-vitamin, non-herbal dietary supplements. CAM use was greater among women than men and among whites than blacks; its use increased with higher education levels and poorer general health status.