We have analyzed 44 consecutive patients with significant ST-segment depression during the exercise stress test, with the aim of testing the ability of localizing the coronary stenoses. There was a significant correlation only between maximal ST-segment depression in V1-V4 and stenosis in the left anterior descending artery (r = 0.402, p = 0.0067), but the accuracy of the presence of ischemic ST depression in anterior leads to detect disease of the left anterior descending artery was 59% (26 correct, 18 wrong). The low lateral leads (V5 and V6) were the more accurate to detect coronary disease, as much for the left anterior descending artery as for the right or the circumflex coronary arteries. We conclude that ST segment depressions are of little value to localize the coronary stenoses.