The present study was designed to evaluate whether the presence of renal disease during percutaneous coronary intervention (PCI) is associated with worse outcomes at 1 year in a multicenter study. The incidence of death, myocardial infarction, coronary artery bypass grafting, repeat PCI, and repeat revascularization were prospectively collected on 4,602 patients (6,542 lesions) in 2 waves of patients who underwent PCI in 17 centers between July 1997 and June 1999. Renal disease was defined as the presence of an increased creatinine level in a patient with a history or presence of renal failure treated with low protein diet or dialysis. Patients with renal disease (n = 192) were older and more likely to have diabetes, heart failure, reduced ejection fraction, known coronary disease, and multivessel disease than patients without renal disease (n = 4,410). Rates of stenting were equivalent (68.2% vs 73.0%, p = NS). Patients with renal disease had lower angiographic success (84.9% vs 92.8%, p <0.001) and higher mortality, both in-hospital (5.7% vs 1.2%, p <0.001) and at 1 year (19.7% vs 4.4%, p <0.0001). After adjusting for clinical, demographic, and angiographic differences, renal disease remained an independent predictor of in-hospital (odds ratio 3.81, 95% confidence interval 1.70 to 8.58) and 1-year (risk ratio 2.46, 95% confidence interval 1.64 to 3.68) mortality. Renal disease conferred additional mortality risk in established high-risk clinical subgroups. In conclusion, after adjusting for a higher frequency of co-morbidities, renal disease remains a strong and independent predictor of increased in-hospital and 1-year mortality after PCI and is additive to other clinical markers of worse outcome.