Despite the established benefits of cardiac rehabilitation (CR) in improving health outcomes for people with cardiovascular disease, adherence to regular physical activity at recommended levels remains suboptimal. Self-efficacy has been shown to be an important mediator of health behaviour, including exercise. To assess the psychometric properties of Bandura's exercise self-efficacy (ESE) scale in an Australian CR setting. Validation study. Cardiac rehabilitation. One hundred and ten patients (Mean: 60.11, S.D.: 10.57 years). Participants completed a six-minute walk test (6MWT) and Bandura's exercise self-efficacy scale at enrollment and on completion of a 6-week CR program. Bandura's ESE scale had a single factor structure with high internal consistency (0.95), and demonstrated no floor or ceiling effects. A comparison of ESE scores by distance walked on 6MWT indicated those who recorded more than 500 m at baseline had significantly higher ESE scores (Mean: 116.26, S.D.: 32.02 m) than those patients who only achieved up to 400 m on the 6MWT at baseline (Mean: 89.94, S.D.: 29.47 m) (p=0.044). A positive and significant correlation between the change in scores on the ESE scale and the change in the 6MWT distance (r=0.28, p=0.035) was seen. The ESE scale was a robust measure of exercise self-efficacy over the range of patients attending this outpatient cardiac rehabilitation program. Interventions to improve self-efficacy may increase CR patient's efficacy for regular physical activity.