Strategies to prevent adult osteoporosis are best undertaken during childhood and adolescence, when the greatest amount of bone mineral density is acquired. This study examines pediatricians' knowledge and practices regarding osteoporosis prevention.One hundred eighty-seven primary care pediatricians from San Diego and Imperial Counties responded to a 44-item mailed survey that measured physician knowledge, attitudes, and practices regarding osteoporosis prevention.Knowledge of U.S. RDA for calcium in children and adolescents was limited, with only 23.7 and 32.3% of pediatricians correctly identifying the recommended values for children and adolescents, respectively. Thirty-eight percent of respondents regarded osteoporosis prevention to be an important issue, and less than half reported that they counseled patients for osteoporosis prevention. Of those pediatricians who did perform osteoporosis counseling, the two most frequently cited motivators for counseling were that counseling is recommended by professional boards and having a personal or professional interest in osteoporosis prevention. The most commonly reported barriers to counseling were other issues taking greater priority and having insufficient time to undertake counseling for osteoporosis prevention.Osteoporosis prevention should begin in childhood and adolescence. This study suggests that many pediatricians do not counsel patients to reduce osteoporosis risk, nor do they consider this an important issue. Furthermore, they may not have full knowledge about how to prevent osteoporosis.