Background: Patients with acute myocardial infarction (AMI) usually complain of typical chest pain. Therefore patients with AMI who complains atypical chest pain often are misdiagnosed and have delayed treatment. Method: A total of 29,767 eligible patients enrolled in Korean Acute Myocardial Infarction Registry (KAMIR) and Registry of Korean Patients with Acute Myocardial Infarction (KorMI) divided to the patients who complains typical symptom (typical group; n=23,861) and atypical symptom (atypical group; n=5,906). We compared the clinical, procedural characteristics and evaluated 1-year major adverse cardiac events (MACEs) including death, myocardial infarction (MI), target vessel revasculization (TVR) and coronary artery bypass grafting (CABG) between the groups. Result: Atypical group was older and had more prevalence with female gender, killip class IV, hypertension, diabetes mellitus, hyperlipidemia and diagnosis of non ST-segment elevation myocardial infarction (NSTEMI), whereas typical group had more prevalence with smoking. Procedural findings showed that atypical group had more involvement of left main stem, complex lesion type and less PCI rate (87.3% vs. 72.1%, p<0.001), lower success rate of percutaneous coronary intervention (PCI) (96.1% vs. 92.5%, p<0.001). In-hospital mortality was higher in atypical group than typical group (4.2% vs. 9.4%, p<0.001). At 1-year, atypical group had the higher incidence of cardiac death (8.8% vs. 18.3%, p<0.001), MI (1.5% vs. 2.2%, p=0.003) and the composite of MACEs (21.0% vs. 31.4%, p<0.001). On multivariate analysis, atypical symptoms (adjusted odd ratio [OR] 1.20; 95% confidence interval [CI] 1.10-1.29; p=0.001) was the independent factor of 1-year MACE as well as hypertension, diabetes mellitus, old age, involvement of left main coronary artery, and killip class IV. Conclusion: AMI patients who complain of atypical symptom have worse clinical outcomes compared with the patients who complain of typical symptom. We should not neglect the diagnosis of AMI when the patients complains atypical symptom, especially in elderly female patients with hypertension, diabetes mellitus and dyslipidemia.