The precaution adoption process model was used to examine the predictors of 2 behaviors recommended to reduce the risk of developing osteoporosis: calcium consumption and weight-bearing exercise. A total of 452 premenopausal women completed a mailed questionnaire assessing stage in the precaution adoption process and 12 knowledge and attitudinal variables. Participants were also given an opportunity to request information about osteoporosis. In all, 11 of the 12 knowledge and attitudinal variables were associated with calcium stage; 8 were associated with exercise stage. Information requests were associated with both calcium and exercise stage. Findings provide substantial support for the precaution adoption process model and suggest that the model can be usefully applied in this area to increase understanding of why many women do not practice behaviors that could reduce their risk of developing osteoporosis.