Background : Coronary slow-reflow phenomenon (CSFP) and Contrast-Induced Nephropathy (CIN) are associated with an increased risk of major cardiovascular adverse events. This study aimed to evaluate the relationship between serum Urotensin II molecule (U-II ) levels and CIN in patients with CSFP undergoing percutaneous coronary intervention (PCI). Methods: We enrolled 227 patients (161 male and 66 female; mean age: 61,44 ± 12,44 years) with angiographically diagnosed CSFP. The patients were divided into two groups according to CIN development (Non-CIN (n=206) and CIN group (n=21)). Results: CIN was observed in 9,25%(n=21) of the CSFP patients. Serum U-II level was significantly higher in CIN group than in non-CIN group (6,79±2,2 vs. 3±1,29, p<0.001). One year clinical follow-up findings including all-cause mortality (7(33,3%) vs. 24(11,7%), p=0,013), cardiovascular death(7(33,3%) vs. 18(8,7%), p=0,003) and Major Adverse cardiovascular events (MACE) (10(47,6%) vs. 46(22,4%), p: 0,011) were significantly higher in CIN group. We also performed forward conditional logistic regression analysis and found that U-II (Odds ratio (OR)= 3,983; 95% confidence interval (CI): 2,25 to 7,052; p < 0.001) and Mehran score (OR=1,228, 95% CI: 1,083-1,393, p=0,001) were independently predicted CIN development in patients with CSFP. Conclusions: Baseline serum U-II concentrations and higher Mehran scores are independently associated with CIN in CSFP patients. One year clinical follow-up findings including all-cause mortality, cardiovascular death and MACE were significantly higher in CIN group, but stroke and myocardial infarction rates were similar in both groups.