Background It is well established that cardiac rehabilitation (CR) is beneficial in terms of reduction of major adverse cardiovascular events and improvement of functional capacity in patients with coronary heart disease (CHD). However, there has been few studies on cost-effectiveness of CR. CR may be cost-effective if the costs due to participation in the CR program can be balanced by a decrease in medical resource utilization, such as readmission and ER visit. The aim of this study is to evaluate the effect of CR on the medical resource utilization in patients with CHD. Methods Among 3099 patients who were diagnosed as having CHD between 1994 and 2001, 128 patients were enrolled in CR program in Samsung medical center. We compared the CR group with the other 3099 patients as a control group. We obtained data on clinical characteristics of both groups and analyzed the data about the utilization of medical resource such as total number of readmission, total duration of hospitalization, and total number of emergency room (ER) visits. Results Diagnosis of acute myocardial infarction were more frequent in CR group (61.7% vs 28.7%, p<0.001) and mean age was slightly higher in control group (60.8 짹 9.7 vs 56.4 짹 10.4). Mean duration of follow-up in CR group was 5.4 짹 2.1 years, which were statistically longer than that of control group (4.7 짹 2.9 years, p<0.001). In CR group total number of readmission was smaller (1.0 짹 1.2 vs 1.3 짹 1.8, p=0.001) and total duration of hospitalization was shorter than that of control group (4.7 짹 8.3 vs 10.2 짹 26.2, p<0.001). And total number of ER visit was also smaller in CR group than control group (1.1 짹 1.7 vs 1.7 짹 2.5, p<0.001). In multivariate analysis, number of readmission and ER visit are significantly smaller (p<0.05) in CR group than in control group after adjustment for age, sex, clinical diagnosis, number of diseased vessels, and follow-up duration. Conclusion Enrollment in CR program was associated with reduced medical resource utilization, which probably can results in favorable cost-effectiveness in CHD management. Full economic analysis of CR is warranted in proper health policy establishment.