Background: Chronic kidney disease (CKD) is associated with increased risk of adverse cardiovascular events, including contrast induced nephropathy (CIN) after percutaneous coronary intervention (PCI). But, prognostic significance of admission serum creatinine for CIN and mortality in patients with ST elevation myocardial infarction (STEMI) is not known. So, the aim of this study was to evaluate impact of admission serum creatinine on cardiovascular death and CIN in patients with STEMI underwent primary PCI Method: We analyzed 328 consecutive patients with STEMI underwent primary PCI. The patients were divided into two groups according to admission serum creatinine level; group I: ���1.2mg/dl (n=244, 74.4%), group II: >1.2 mg/dL (n=84, 25.6%). Contrast-induced nephropathy was defined as an increase in serum creatinine level >25% or 0.5 mg/dL after 48 hours. We sought CIN and cardiovascular death at 12-month follow-up Result: Baseline clinical characteristics were similar between the two groups except diabetic pateints were more frequent in Group I (p=0.008). Group II was associated with a significantly higher rate of CIN (8.4% vs. 26.9%, p <0.001) and cardiovascular death (6.6% vs. 18.8%, p =0.01) compared with group I. At 12-month follow-up, the death-free survival rate was significantly lower in the group II compared with group I (log rank test p <0.001). Also, when each serum creatinine group was divided according to presensce of CIN, 12-month death-free survival was signicantly different between four groups (94.7% vs. 89.7% vs. 78.9% vs. 59.1%, log rank test p <0.001)(Figure). Conclusion: In STEMI patients treated with primary PCI, increased admission serum creatinine was strongly associated with 12-month mortality and CIN.