OBJECTIVE: To compare the exercise capacity after cardiac rehabilitation (CR) in patients with percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery. METHOD: 27 patients who underwent PCI and 18 patients who underwent CABG surgery were included. All the subjects performed supervised exercise training for 6~8 weeks at hospital and self-exercise at community for additional 16~18 weeks. Exercise capacity was measured by symptom limited graded exercise tests at study entry and 6 months later. RESULTS: After 6 months of CR, maximal oxygen consumption (VO2max) was significantly increased, resting heart rate (HR) and submaximal rate pressure product (RPP) were significantly decreased in both groups (p<0.05). There were no significant change of maximal HR in both groups (p<0.05). Maximal RPP in CABG increased significantly (p<0.05) but did not change significantly in PCI group. Resting HR was significantly higher, VO2max was significantly lower in CABG group than PCI group at study entry (p<0.05). Resting HR was not significantly different in both groups but, VO2max was still lower in CABG group than PCI group even after 6 months of CR (p<0.05). CONCLUSION: The cardiac rehabilitation program was effective in both PCI and CABG group. Although VO2max in PCI group was higher than CABG group after 6 month CR, the range of improvement was greater in CABG group than PCI group.