Purpose: The study aimed to apply Tai Chi exercise to patients with coronary artery disease for 6 months, and to examine changes on body composition, physical strength, and cardiovascular risks. Methods: Applying a quasi experimental design with a nonequivalent control group, 90 subjects with cardiovascular disease were recruited at C university hospital. For 6 months, 44 subjects performed Tai Chi exercise once a week and daily home exercise, while 46 subjects did not. Body composition was assessed by body mass index, % body fat, and waist-hip ratio; physical strength by balance, mobility, flexibility, grip strength, and back muscle strength; and cardiovascular risk checklist for fixed and modifiable risk factors. Data were analyzed by SPSS/WIN program with ANCOVA to consider group differences at the pretest. Results: The subjects were 66 years old in average. In 6 months, Tai Chi group improved significantly in balance, mobility, and flexibility with decreased modifiable cardiovascular risks after adjusting for the pretest scores. Conclusion: Tai Chi exercise was safely applicable to individuals with coronary artery disease, and effective in some measures of physical strength and modifiable cardiovascular risks. It could be an alternative exercise for outpatient cardiac rehabilitation program in this population.