The stages of change model has shown promise in advancing knowledge about smoking behavior change and other negative addictive behaviors. The model was applied to the study of exercise, a healthy rather than unhealthy behavior. A stages of exercise behavior questionnaire was administered to a sample of 235 employees. Next, the ability of a second questionnaire measuring physical activity behavior to differentiate employees according to stage of exercise was tested. Results revealed that 51% of employees were participating in no physical activity (Precontemplation, Contemplatation) and 49% were participating in occasional or regular physical activity (Preparation, Action, Maintenance). Scores on physical activity behavior items significantly differentiated employees among the stages. This model developed on smoking and other behaviors can be generalized to exercise behavior. Understanding the stages of exercise behavior could yield important information for enhancing rates of participation in physical activity.