We evaluated whether prior statin therapy reduces in-hospital ventricular tachycardia/ventricular fibrillation (VT/VF) in percutaneous coronary intervention (PCI) patients with acute myocardial infarction (MI). Among the 1177 patients from the Acute Myocardial Infarction Registry-National Institutes of Health (KAMIR-NIH), 823 (70%) patients received prior statin therapy. Prior statin therapy was associated with a reduced risk of VT/VF events in both adjusted propensity score analysis (odds ratio [OR] 0.414, 95% confidence interval [CI], 0.198-0.865, P = .019) and adjusted inverse probability of treatment weight analysis (OR 0.463, 95% CI, 0.216-0.994, P = .048). The risk of in-hospital death did not differ significantly between those with or without prior statin therapy (hazard ratio [HR] 0.416, 95% CI, 0.112-1.548, P = .191). Major adverse cardiac events occurred in 116 (8.9%) patients during follow-up. Prior statin therapy was associated with a lower risk of major adverse cardiac events during the follow-up period (HR 0.486, 95% CI, 0.243-0.974, P = .042); however, this was mainly driven by reduced noncardiac death. Prior statin therapy might reduce the incidence of serious cardiac tachyarrhythmia, such as VT/VF, in patients with MI undergoing PCI. However, the reduction in VT/VF due to prior statin therapy did not improve short- and long-term clinical outcomes.