Diabetes mellitus is an independent predictor of nephropathy after percutaneous coronary intervention (PCI). The outcomes of patients with diabetes with normal baseline serum creatinine who undergo PCI remain underevaluated. The aim of the present study was to assess the incidence, outcomes, and correlates of post-PCI nephropathy in this subset. The study cohort consisted of 570 patients with diabetes with normal serum creatinine (< or =1.3 mg/dl) who underwent PCI from August 2004 to December 2006. Patients aged >75 years and those presenting with either acute myocardial infarctions or cardiogenic shock were excluded. Post-PCI nephropathy was defined as a > or =25% increase in baseline creatinine. The study end points were post-PCI nephropathy and major adverse cardiac events at 6 months. Logistic regression was performed to identify independent predictors. Post-PCI nephropathy occurred in 70 patients (incidence 12.3%). These patients were more likely to be women (55.7% vs 35.5%, p = 0.001) and to have histories of congestive heart failure (24.2% vs 14.7%, p = 0.048). Entry-site complications (hematoma, pseudoaneurysm) and the need for blood transfusion (16.7% vs 1.7%, p <0.001) were more common in this group. In-hospital mortality (8.6% vs 0.2%, p <0.001) and length of stay (4.51 +/- 5.2 vs 2.23 +/- 2.9 days, p <0.001) were significantly higher in the group with post-PCI nephropathy. No study patient required dialysis. At 6 months, major adverse cardiac events were markedly higher in patients with post-PCI nephropathy (21.4% vs 6.0%, p <0.001), driven by death and revascularization. Independent predictors of post-PCI nephropathy were lower body mass index and blood transfusion. Post-PCI nephropathy independently predicted major adverse cardiac events (hazard ratio 4.3, 95% confidence interval 2.1 to 8.6, p <0.001). In conclusion, post-PCI nephropathy occurred in 12.3% of patients with diabetes with normal baseline serum creatinine and carried a significant detrimental impact on prognosis. The requirement for blood transfusions was the strongest correlate identified.