Ischemic heart disease (IHD) contributes to a high percentage of morbidity and mortality of diabetes. A predictor of IHD can lead to an early diagnosis to prevent progression and to reduce future clinical events. The aim of the study was to examine whether the spectrum analysis of radial pressure wave can predict IHD in patients with Type 2 diabetes. Radial pressure wave was measured by a piezoresistive sensor in 1,137 (Male: 681, Female: 456) Type 2 diabetic patients with IHD (n=158) and without IHD (n=979), recruited from the Division of Endocrinology & Metabolism of Zhongxiao Branch of Taipei City Hospital. For each patient, spectrum analysis of radial pressure wave was calculated and transformed into Fourier series coefficients Cn. The means of first (C1), second (C2), and third (C3) harmonic of arterial pulse were significantly higher in patients with IHD (C1:0.996u00b10.104, C2: 0.529u00b10.099, C3:0.273u00b10.083) than in patients without IHD (C1:0.964u00b10.100, P<0.01; C2:0.514u00b10.104, P<0.1; C3:0.256u00b10.082, P<0.05, respectively). Chi-square test proved there were associations between C1~C3 and IHD (C1: P <0.01, C2: P <0.01, and C3: P <0.05, respectively). The risks of IHD in patients with diabetes were raised by the increments of C1 (Odds ratio: 1.80, 95% C.I. 1.28-2.52, P<0.01), C2 (Odds ratio: 1.57, 95% C.I. 1.12-2.21, P<0.01), and C3 (Odds ratio: 1.45, 95% C.I. 1.03-2.05, P<0.05). Multiple linear regression analysis showed C2, C3, gender, waist, triglyceride, low-density lipoprotein cholesterol, and duration of diabetes were associated with IHD(R=0.505, P=0.06 ). The preliminary findings from the study identified the first, second, and third harmonics of radial pressure wave could be a set of important predictors for early diagnosis of IHD in type 2 diabetic patients.