Acute renal failure requiring dialysis is a rare but serious complication after percutaneous coronary interventions (PCI), associated with high in-hospital mortality and poor long-term survival. We have analyzed the incidence, resource utilization, short- and long-term outcomes, and predictors of dialysis after percutaneous coronary interventions. We studied 51 consecutive patients who were not on dialysis on admission and developed acute renal failure that required in-hospital dialysis after PCI in comparison to the 7,690 patients who did not require dialysis after PCI. Patients who required dialysis were older, with a higher incidence of hypertension, diabetes, prior bypass surgery, chronic renal failure, and a significantly lower left ventricular ejection fraction. Despite similar angiographic success, these patients had a higher incidence of in-hospital mortality (27.5% vs. 1.0%, P < 0.0001), non-Q-wave myocardial infarction (45.7% vs. 14.6%, P < 0.0001), vascular and bleeding complications, and longer hospitalization. At 1-year follow-up, mortality (54.5% vs. 6.4%, P < 0.0001), myocardial infarction (4.5% vs. 1.6%, P = 0.006), and event-free survival (38.6% vs. 72.0%, P < 0.0001) were significantly worse in patients who required dialysis compared to patients who did not. Multivariate analysis revealed in-hospital dialysis and an increase in baseline serum creatinine levels as the most important predictors of in-hospital and long-term mortality. Thus, acute renal failure that requires dialysis after percutaneous coronary interventions is associated with very high in-hospital and 1-year mortality rates and a dramatic increase in hospital resource utilization.