Aim To assess the relationship between neopterin levels and left ventricular remodeling in patients with actue myocardial infarction undergoing primary percutaneous coronary intervention （PCI）. Methods We prospectively assessed 148 ST-segment elevation myocardial infarction （STEMI） patients undergoing primary PCI between January 2011 and November 2012. Serum neopterin,brain natriuretic peptide （BNP） and high sensitivity C-reactive protein （hs-CRP） concentrations were measured immediately before primary PCI. Echocardiographycally assessment was performed at 24 h and 12 months after myocardial infarction. Left ventricular remodeling （LVR） was defined as >20% increase in left ventricular （LV） end-diastolic volume at 12 months of follow-up compared with baseline. Results At one year,32 patients showed LVR and 116 patients had no LVR. Plasma neopterin levels were significantly higher in patients with LVR than in those without LVR （9.01±1.68 nmol/L vs 4.95±0.83 nmol/L,P<0.001）. Linear regression analysis showed neopterin levels were positively correlated with increased levels of follow-up left ventricular end-diastolic volume （LVEDV） （r0.749,P<0.001）. Logistic analysis after adjustment for relevant confounders,neopterin levels were found to be an independent predictor of LVR（OR3.895,95%CI 2.242～6.767,P<0.001）. ROC analysis showed an area under the curve of 0.973 for neopterin（95%CI 0.948～0.998,P<0.001） regarding LVR. The optimal neopterin cut-off point was 6.38 nmol/L with a sensitivity of 93.8% and a specificity of 94.8%. Conclusion In STEMI patients undergoing primary PCI,neopterin levels are closely related with LVR,high neopterin levels predict LVR at 1-year follow-up.