Sixty-eight patients underwent percutaneous transluminal coronary angioplasty (PTCA) for multiple coronary stenoses. Lesions involved one coronary vessel in 24 patients, two in 34, and three or more vessels in 10 patients. The primary patient success rate was 96%, and we successfully dilated 162 (91%) of 179 significant (i.e., greater than 70% obstructive) coronary lesions, mean 2.4 lesions/patient. Complete coronary revascularization was achieved in 24 patients (Group 1), while major narrowings were not dilated either by intention or due to failure of dilation in 42 others (Group 2). The clinical state of the patients improved markedly after successful PTCA, and 44 (72%) of 61 were in the New York Heart Association Functional Class I or II 3 to 24 months later. In keeping with the clinical results, there was a significant improvement in treadmill exercise performance, in both groups. Patients with complete revascularization, however, tended to exercise longer (NS) to a greater heart rate (P less than 0.004) with less or no ischemic ST depression on ECG (P less than 0.04). Complications were few and limited to patients undergoing PTCA for unstable angina pectoris or following acute myocardial infarction. One patient (1%) died, two (3%) had Q-wave infarction and one patient sustained a cerebral embolus during catheterization. Restenosis was observed in 6 (29%) of 21 consecutive patients recatheterized 6 to 12 months (or sooner for symptoms) after successful PTCA. Four patients underwent a repeat PTCA, one was referred for coronary artery bypass grafting (CABG), and in one restenosis was minor and symptoms were mild. PTCA should be considered in patients with multiple coronary stenoses in whom all or most of the significant lesions can be dilated. Partial revascularization by PTCA is clinically useful and may be preferable to CABG in patients in whom the surgical risk is increased.