Background: There are few available data of the incidence, predictors, and clinical outcome of newly developed cardiogenic shock (CS) during hospitalization in patients with acute myocardial infarction (AMI) after successful revascularization. Methods and Results: We analyzed 9,056 AMI patients without CS or Killip class IV on admission who underwent successful percutaneous coronary intervention from Korea Acute Myocardial Infarction Registry (KAMIR) between Oct. 2005 and Jan. 2008. Of these, 234 patients (2.6%) developed CS during their hospitalization. Patients with CS were older (68짹12 vs. 62짹12 years), more common in female gender (38.5% vs. 26.8%), higher Killip class (49.1% vs. 18.9%), more common history of diabetes (34.6% vs. 26.0%) and more ST-elevation MI (80.8% vs. 63.0%) than those without CS (p<0.005 respectively). Patients with CS also were more likely to have lower left ventricular ejection fraction (LVEF) (44.2짹13.0% vs. 52.8짹17.6%), lower creatinine clearance (51.9짹25.7 vs. 72.4짹36.5) and longer duration of CCU stay (6.1짹6.1 vs. 3.4짹3.2 days) than those without CS. Multi-vessel disease or left main disease (68.8% vs. 56.3%) and complex target lesion (86.3% vs. 78.8%) were more frequent in patients with CS than those without CS (p<0.005 respectively). Patients with CS had higher incidence of in-hospital mortality than those without CS (35.5% vs. 1.1%, p<0.001). LVEF [Odds ratio (OR)=0.934; 95% Confidence interval (CI)=0.916-0.952], creatinine clearance (OR=0.977; 95% CI=0.964-0.990), age (OR=1.059; 95% CI=1.029-1.090), Killip class II or III (OR=2.135; 95% CI=1.324-3.445), and developed CS during hospitalization (OR=15.368; 95% CI=9.103-25.946) were independent predictors for in-hospital mortality in AMI patients. The independent predictors of development of CS during hospitalization in AMI patient were LVEF (OR=0.962; 95% CI=0.950-0.974), creatinine clearance (OR=0.979; 95% CI=0.971-0.986), Killip class II or III (OR=2.615; 95% CI=1.894-3.612), complex target lesion (OR=1.625; 95% CI=1.035-2.550), and multi-vessel or LM disease (OR=1.625; 95% CI=1.035-2.550). Conclusion: CS during hospitalization was mainly developed in high risk patients and associated with in-hospital mortality in AMI patients. Intensive treatment and careful monitoring should be needed in AMI patients even though successful revascularization, especially with low LVEF and creatinine clearance, high Killip class, complex target lesion, and multi-vessel or LM disease.