With the aim of investigating the functional result of the coronary angioplasty (PTCA) and verifying the predictive value of the exercise test for detecting restenosis, 165 patients who underwent successful PTCA were evaluated through exercise stress tests performed 10, 75 and 165 days after PTCA and through coronary angiography performed 5 to 6 months after PTCA. The percentage of negative tests and the rate-pressure product (RPP) increased significantly with respect to the tests performed before PTCA, both in patients with single-vessel and those with multivessel disease. Maximal ST segment depression and ST/HR were significantly reduced only in patients with complete revascularization. The percentage of positive tests 10 days after PTCA was lower in patients with single-vessel than in those with multivessel disease (2.5% versus 10.8%) and, of the latter, in patients with complete rather than incomplete revascularization (0% versus 13.5%). In patients with complete revascularization, the mean exercise time rose significantly (703 s versus 538 s). The percentage of positive tests increased progressively with time, in accordance with probable increasing restenosis. In comparison with the results of angiography, sensitivity of the exercise stress test proved to be poor (59%), especially in patients with single-vessel disease (45%), while the specificity was very high (98%). The predictive value of a negative test was 77% in patients with multi-vessel and 87% in patients with single-vessel disease. The predictive value of a positive test was over 90% in both groups of patients.