Data about the primary success and complication rates following transluminal coronary angioplasty are comparable worldwide. Reports on the frequency of recurrences, however, differ considerably. Data concerning factors enhancing the risk of restenosis are contradictory. We compared a group of 62 patients with angiographically confirmed restenosis with a group of 62 patients without restenosis. There were no significant differences with regard to age, sex, onset of symptoms and severity of angina pectoris, number of previous infarctions, incidence of multivessel disease, maximum size of the balloon catheters used and primary dilatation results. The following factors were significantly associated with the occurrence of restenosis: high-grade stenoses prior to dilatation, stenoses involving long segments of coronary arteries, eccentric stenoses, the necessity to apply high balloon pressures, long duration of balloon inflation, and also the patient being overweight, a nonsmoker and having undergone an alteration in continuous treatment.