The study aims to evaluate the relation between the decisional balance and causality orientation of exercise. Stage of Exercise Behavior Change scale (Cardianl, 1997), Decisional Balance questionnaire (Plotnikoff et al, 2001) and Causality Orientation of Exercise questionnaire (Rose, Markland & Parfitt, 2001) was used. The multivariate discriminant analysis was used to predict the stages of behavior change based on decisional balance and causality orientation. The results showed that there is a significant and positive relation between the perceived advantages of exercise and control and autonomy orientations. Decisional balance and aspects of causality orientation of exercise makes a powerful predicative model to predict the membership of participants in various stages of behavior change. This means that it is necessary to consider the role of exercise motivation in various stages of exercise behavior and its relation with components of transtheoretical model to make a powerful predictive model.