Neutrophil-to-lymphocyte ratio (NLR) has been reported to predict cardiovascular risks and mortality in coronary artery diseases. We aimed to evaluate the capacity of NLR to predict long-term mortality in Chinese patients presenting with ST-segment elevation myocardial infarction (STEMI). We recorded NLR at admission, 24 or 72 hours after admission, and at discharge (14 +/- 2 days) of 692 patients presenting with STEMI at Xuanwu hospital, Beijing between 2002 and 2005, and assessed the capacity of NLR to predict mortality during follow up (median 9.43, interquartile range (IQR) 8.65-10.28 years). Backward stepwise multivariate Cox regression revealed that average inpatient NLR (NLRaverage) predicted all-cause mortality (Hazard ratio 1.481) more accurately than absolute leukocyte and neutrophil counts (P<0.001). When patients were stratified into tertiles by NLRaverage (T-1 NLR<3.16, T-3 NLR>4.75), patients in T-3 exhibited a 4.621-fold higher risk of mortality than patients in T-1 (P=0.002). Patients in T-3 had a significantly higher incidence of all-cause mortality (10.00%) than T-1 (2.17%) and T-2 (4.31%), cardiac-mortality (8.70%) than T-1 (2.17%) and T-2 (4.31%), hypotension (20.00%) than T-1 (5.65%) and T-2 (12.93%), arrhythmia (43.91%) than T-1 (24.14%) and T-2 (24.35%), and defibrillation (7.83%) than T-1 (1.74%) and T-2 (5.17%) in hospital; and suffered from higher mortality (46.09%) than T-1 (9.13%) and T-2 (29.74%), cardiac mortality (27.83%) than T-1 (5.22%) and T-2 (15.52%) and MACE events (36.52%) than T-1 (13.04%) and T-2 (31.9%) during long-term follow-up. Average NLR was a useful and powerful predictor of mortality and adverse-outcomes in Chinese patients presenting with STEMI.