Context: To summarize and evaluate the available evidence from controlled clinical trials of tai chi (TC) exercise for patients with heart disease. Search methods: Fourteen databases were searched up to November 2010 with the terms tai chi, taichi, tai ji, taiji, taijichuan, cardiac, heart, coronary, myocardial, and atrial fibrillation in the title, abstract, or key words. No language restrictions were imposed. The quality and validity of randomized clinical trials (RCTs) were evaluated using the Jadad Scale. The strength of the evidence for all included studies was evaluated using the Oxford Centre for Evidence-based Medicine Levels of Evidence. Results: Nine studies including 5 RCTs and 4 nonrandomized controlled clinical trials met the inclusion criteria. Three studies examined the effectiveness of TC exercise for patients with chronic heart failure (CHF), and 6 studies examined the effectiveness of TC exercise among patients with coronary heart disease (CHD). Overall, these studies demonstrated favorable effects of TC exercise for the patients with heart disease. Conclusions: The existing evidence suggests that TC exercise is a good option for heart patients with very limited exercise tolerance and can be an adjunct to rehabilitation programs for patients with CHD or CHF.