This study examined the application of constructs concerning stage of readiness to change and self-efficacy to exercise. We developed two scales to measure stages of change for exercise behavior. Prevalence information on a sample of 1,063 government employees and 429 hospital employees was then obtained. Next, the ability of a questionnaire measuring exercise self-efficacy to differentiate employees according to stage of readiness to change was tested. Results from both stages-of-change scales revealed that 34-39% of employees were regularly participating in physical activity. Scores on efficacy items significantly differentiated employees at most stages. Results indicated employees who had not yet begun to exercise, in contrast with those who exercised regularly, had little confidence in their ability to exercise. Continued work at understanding the stages of exercise behavior and exercise self-efficacy could yield important information for enhancing exercise adoption and adherence.