This study was done to determine the value of thallium-201 stress myocardial perfusion scanning for identifying disease in the individual coronary arteries. Segement analysis of rest and stress myocardial perfusion scanning was performed in 65 subjects who underwent coronary arteriography. Anterolateral wall detects had a sensitivity of 70%, a spectivity of 92%, and a predicitive accuracy of 93.3% for identifying left anterior descending(LAD) coronary artery disease(CAD). Anteroseptal wall defects had a sensitivy of 62.5%, a specificity of 80%, and a predictive accuracy of 83.3% for identifying LAD CAD. Septal wall defects had a sensitivity of 67.5%, a specificity of 92%, and a predictive accuracy of 94.4% for identifying LAD CAD. Inferior wall defects had a sensitivity of 65.4%, a specificity of 89.7%, and a predictive accuracy of 80.9% for identifying right CAD. Posterolateral wall defects had a identifying left circumflex CAD. Thus, although senmental analysis of stress myocardial perfusin scanning can identify LAD CAD with high sensitivity and specificity, only moderate sensitivity and specificity are achieved in identifying right CAD or left circumflex CAD. But stress myocardial perfusion scanning has tendency to identify the most severely ischemic area, use of segmental analysis may be of benefit in the evaluation of patients with ischemic heart disease before or after coronary artery bypass graft and percutaneous transluminal coronary angioplasty.