Background Fever is a common finding after primary percutaneous coronary intervention (PPCI) in patients with acute myocardial infarction (AMI). However, its prognostic value is not validated yet. Methods 531 consecutive patients who underwent PPCI due to acute myocardial infarction were enrolled. Body temperature (BT) was checked every 6 hours for 5 days after PPCI. Patients were divided into two groups as group N; peak BT<37.8oC and Group F; peak BT���37.8oC. 1-year major adverse cardiovascular events (MACE; cardiac death, myocardial infarction, target lesion revascularization, stent thrombosis) were compared. Results Peak BT���37.8oC was developed in 19.4% (103/531). There was no difference in angiographic characteristics between 2 groups. WBC count and hsCRP were higher in group F than group N (12118짹4167 vs. 10716짹3815, p=0.001; 2.39짹5.02 vs. 0.85짹2.70, p=0.012). Previous MI history and ejection fraction were lower in Group F than Group N (0.0% vs. 4.4%, p=0.033; 46짹9% vs. 49짹 9%, p=0.001). MACE were higher in Group F (15.5% vs 7.7% in group N, p=0.014). Multivariate analysis revealed that peak BT���37.8oC and LAD lesion were an independent predictor of 1 year MACE (peak BT���37.8oC, OR 1.98, 95% CI 1.02-3.81, p=0.042; LAD lesion, 2.22, 1.16-4.24, 0.016). Conclusions Increased BT after PPCI in AMI can predict later adverse clinical outcome.