UNLABELLED To test if a low Q wave voltage and its faulty increase after exercise is an additional sign of myocardial ischemia, 64 pts with no previous myocardial infarction, bundle branch block or left ventricular hypertrophy were studied by a treadmill test and coronary angiography. Nineteen had single vessel disease (SVD), 21 double vessel disease (DVD), 4 triple vessel disease (TVD) and 20 normal coronary arteries. Sensitivity (SENS), specificity (SPEC) and predictive value (P) of Q wave changes have resulted as follows: 84%, 55%, 80.4%, respectively, compared to 79.5%, 75%, 87.5% of ST modifications associated or not with angina. The SENS of Q wave changes was 72% in SVD and 92% in multivessel disease (p less than 0.05). In 68% of our pts ST and Q wave changes gave concordant results and their combination increased SENS, SPEC, PV to 90.1%, 80%, 90.3%. IN CONCLUSION Q wave analysis can provide further evidence of myocardial ischemia and can increase SENS, SPEC of stress test. In our experience Q wave is a more sensitive finding than ST depression in multivessel disease.