The effect of balloon compliance on the safety and outcome of percutaneous transluminal coronary angioplasty (PTCA) is controversial. It has been proposed that PTCA balloons constructed from compliant polymers contribute to an increased risk of angiographic coronary dissection and potentially to adverse clinical results. To determine the effect of balloon material compliance on PTCA outcome, 1,076 PTCA procedures using balloons differing in compliance characteristics (polyethylene teraphthalate [noncompliant], polyethylene intermediately compliant] or polyolefincopolymer [compliant]) were retrospectively analyzed. Baseline clinical, angiographic and procedural variables were similar among the 3 balloon material groups. In the noncompliant, intermediately compliant and compliant groups, the occurrence rates of intimal tears (10, 14 and 10%, respectively; p = NS for all comparisons) and coronary dissection (7, 9 and 8%, respectively; all p = NS) were also equivalent. The rates of acute occlusion, myocardial infarction, emergency bypass surgery and death were low and similar, and likewise unaffected by balloon material. The results provide evidence that the occurrence of adverse outcomes after PTCA is unrelated to balloon material compliance and support the clinical safety of balloons constructed of compliant or noncompliant polymers when used for appropriate coronary interventions.