Purpose : To evaluate the utility of quantification of coronary artery calcification using spiral CT. Materials and Methods : Spiral CT scans of the heart were obtained in 25 patients with coronary artery disease diagnosed by coronary angiography and in six controls without coronary artery disease. Spiral CT was performed with 3 mm collimation at 3 mmsec table speed and the obtained volume data of the heart was reconstructed at 2 mm intervals. Total calcium scores of the 30 contiguous slices of the proximal coronary artery were calculated based on the areas and peak density. Two groups were compared for total scores and sensitivity, and specificity and positive predictive values were calculated. Results : The number of subjects with coronary calcification(total calcium score>0) detected by spiral CT were 20(80%) of 25 with coronary artery disease and 2(33%) of 6 without coronary artery disease. The sensitivity, specificity, and positive predictive values were 80%, 67% and 91%respectively. Sensitivity was 64%, specificity was 80% in patients aged$leq$60. Sensitivity was 76% and specificity was 83%(total calcium score 10). Conclusion : Quantification of coronary artery calcification using spiral CT has low specificity in the older group and low sensitivity in the younger group ; the procedure is therefore may not be useful as a noninvase screening test to predict the prescence of coronary artery disease. In the younger group, however, a cardiac workup is strongly indicated if calcification is present.