This longitudinal study examined exercise behavior patterns (i.e., maintainers, irregular, and inactive) in cardiac patients, and investigate the sociodemographic, clinical, psychosocial, and environmental correlates of exercise patterns. 661 cardiac in-patients from 3 hospitals consented to participate (75% response rate) and were re-assessed 9 and 18 (81% retention) months postdischarge. Exercise patterns were assessed via the Health-Promoting Lifestyle Profile II subscale using a median split. Of 417 participants (mean age 63.1 ± 10.2) with complete data, 42.2% were classified as Exercise Maintainers, 21.3% as Irregular Exercisers, and 26.1% as Inactive. Multinomial logistic regression revealed that Exercise Maintainers were more likely to be male, have exercised prior to their diagnosis, attend cardiac rehabilitation, perceive fewer exercise barriers, and were less likely to be current-smokers, past-smokers, or attribute the cause of their disease to their own behavior. Patients more likely to maintain exercise have positive perceptions and utilize cardiac rehabilitation.