The objective of the present study was to evaluate the effect of a six-month Tai Chi (TC) exercise cardiac rehabilitation program on two prognostic factors of cardiac events, rate-pressure product and rate-pressure product reserve, in patients with coronary artery disease (CAD). Patients (N = 54) with CAD were recruited from the clinics of cardiology and cardiovascular surgery at a regional hospital in Taiwan. Twenty-two of them enrolled in the TC rehabilitation program which consisted of weekly 90-min sessions of Yang's style TC for six months in addition to receiving usual care. The remaining 32 patients received usual care only. Modified Bruce treadmill exercise test was performed to evaluate their exercise test responses at baseline and at six months. The change over time was significantly different between the TC and control group in peak rate-pressure product (RPP) (interaction between group and time, p = 0.029) and in RPP reserve (interaction between group and time p = 0.009) over the six-month period, there was a decrease in peak RPP of 32.0 mmHg x bpm x 10(-2) and in RPP reserve of 37.4 mmHg x bpm x 10(-2) in the TC group. In conclusion, participating in a six-month TC exercise-based cardiac rehabilitation program was associated with improved peak RPP and RPP reserve during exercise testing in patients with CAD. TC exercise program may lead to a better prognosis for cardiac events in patients with CAD.