Historically, restenosis after coronary angioplasty has been assessed angiographically at about 6 months. The desirability of avoiding routine follow-up angiography as well as the recognition that angiographic and clinical assessments are not necessarily the same has prompted greater interest in following patients clinically after angioplasty. Clinical restenosis has been defined as the composite of death, myocardial infarction, coronary surgery, or additional angioplasty within 6 months of the index procedure. Clinical restenosis was observed in 2,340 of 11,473 patients (20.4%). The mortality at 6 months was only 1%. Although there were somewhat more acute myocardial infarctions and coronary surgical procedures, the most frequent event was additional angioplasty. Angiographic restenosis was noted in 30% of patients without clinical restenosis and in 87% of patients with clinical restenosis (p < 0.0001). Patients with clinical restenosis were less likely to be women, had more systemic hypertension, diabetes mellitus, more severe angina originally, fewer prior myocardial infarctions, more multivessel and left anterior descending artery disease, more multisite procedures, more branch site procedures, and longer and tighter stenoses both before and after the procedure. The year of the procedure did not correlate with restenosis. Clinical restenosis is less common than angiographic restenosis and the most common event is additional angioplasty. Although clinical restenosis is rarely fatal, it does result in inconvenience and additional resource consumption.