OBJECTIVE To examine nutritional supplementation and anabolic steroid (AS) use in adolescent males and females in a multistate, cross-regional study. A secondary purpose of the study was to investigate the knowledge, beliefs, and sources of education on nutritional supplementation and AS in these students. METHODS A confidential self-report survey was administered to 3248 students representing grades 8-12 in 12 states in the continental United States by their teachers during homeroom or physical education class. RESULTS Use of at least one supplement was reported by 71.2% of the adolescents surveyed. The most popular supplements used were multivitamins and high-energy drinks. The use of supplements to increase body mass and strength, and to reduce body fat or mass, increased across grade and was more prevalent in males than females. The number of students that self-reported AS use was 1.6% (2.4% males and 0.8% females). The number of supplements used was related to AS use among adolescents, and this effect was greater among males. Adolescents also seemed willing to take more risks with supplements to achieve their fitness or athletic goals, even if these risks reduced health or caused premature death. CONCLUSIONS This study demonstrates that reliance on nutritional supplements increases as adolescents mature. The apparent willingness of adolescents to use a supplement that may harm their health or shorten their life highlights the need for greater involvement of teachers, coaches, and physicians to provide continued education on the risks and benefits associated with nutritional supplementation and AS use.