OBJECTIVES: The aim of this study is to evaluate the cost-effectiveness of CT coronary angiography (CTCA) and myocardial SPECT for ischemic heart disease in patients with chest pain. METHODS: We assessed cost-effective of CTCA and myocardial SPECT for patients with intermediate risk with pre-test likelihood of 10-90. The model was analyzed by using diagnosis accuracy and QALY. The model using diagnosis accuracy used the number of patients accurately diagnosed among 1000 persons as the effect, and reflecting only the medical expenses for tests as the cost. In the model using QALY, a decision tree was developed and the time horizon was 1 year. Utility weights were calculated using questionnaires for each case from general population. Costs were calculated through analysis of Health Insurance Review & Assessment Service claim data and transition probabilities were estimated from retrospective cohort data. Analyses were conducted from the Healthcare system perspectives. RESULTS: In the model using diagnosis accuracy, CTCA appeared to be more effective (224.41 correct diagnosis) and even less expensive (US$58,819 per 1,000 persons) than myocardial SPECT proposed to be the dominate alternative. In the model using QALY, CTCA showed more effective (0.00040QALYs) and less cost (US$465) than myocardial SPECT. Sensitivity analysis was performed for transition probabilities, utility weights and costs. The results of sensitivity analysis were robust. In subgroup analysis, myocardial SPECT showed cost-effective in patients with pre-test likelihood of 30-60. CONCLUSIONS: In conclusion, cost-effective analysis between CTCA and myocardial SPECT indicated that CTCA was the cost-effective test for both models using diagnosis accuracy and the one using QALY in patients with intermediate risk with pre-test likelihood of 10-90.