Background: There is very little information about the relationship between hyperuricemia, acute kidney injury (AKI) and in-hospital mortality. Methods and Results: With a retrospective analysis of the medical records, 1,247 patients who had percutaneous coronary intervention (PCI) were investigated. AKI was defined as an increase in serum creatinine of ≥0.5mg/dl or ≥50% over baseline within 7 days of PCI. The association of AKI with clinical, biochemical and procedural variables were examined. In addition, the association of hyperuricemia with in-hospital mortality was also examined. Of the 1,247 patients in the study population, 51 (4.1%) experienced AKI after PCI, 15 of whom required hemodialysis. In-hospital mortality occurred in 1.6% (20 of 1,247) in 19.6% (10 of 51) of AKI individuals, and 0.8% (10 of 1,186) of the non-AKI participants (odd ratios, 28.927; 95% confidence intervals, 11.411-73.328; P<0.001). In our study, the most powerful predictors of these variables were acute myocardial infarction, baseline estimated glomerular filtration rate (eGFR) <60ml·min^-1·1.73m^-2, diabetics mellitus, anemia and hyperuricemia. Notably, the incidence of AKI after PCI markedly increased in diabetic or hyperuricemic patients with a baseline eGFR of <60ml·min^-1·1.73m^-2. Conclusions: It is clear that AKI develops due to multiple risk factors. Our results indicate that hyperuricemia is independently associated with an increased risk of in-hospital mortality and AKI in patients treated with PCI. (Circ J 2011; 75: 692-697)