Background: The cold pressor test (CPT) has been used to estimate coronary endothelial function. The aim of this study was to determine whether serum IGF-1 levels may be a marker of the coronary endothelial dysfunction in the patients with normal coronary angiogram. Methods: One hundred ninety patients (mean age=51.2짹12.0; male:female=113:77) with chest pain and normal coronary angiogram were enrolled. During CPT, the mean diastolic flow velocity (MDV) of the distal left anterior descending coronary artery using transthoracic Doppler echocardiography was assessed. CPT%MDV was defined as the percentage changes in MDV during CPT. Serum IGF-1 levels were measured by using sandwich ELISA. Results: 1.There were no significant differences in the clinical characteristics and cardiovascular risk factors between the male and female groups. 2. IGF-1 levels were positively correlated with CPT%MDV in female group (r=0.245, p=0.034). 3. IGF-1 levels were not correlated with CPT%MDV in male group (r=0.002, p=0.983)(See Figure). Conclusions: Serum IGF-I levels may be an useful marker of the coronary endothelial function, especially in women with chest pain and normal coronary angiogram.