In-hospital mortality of patients with cardiogenic shock complicating ST-elevation myocardial infarction (STEMI-CS) ranges from 30% to 50%. The impact of nosocomial infection(NI) is not well addressed in these patients. We queried the 2005-2014 Nationwide Inpatient Sample database to identify patients with STEMI-CS. Incidence of hospital-mortality, acute kidney injury (AKI), length of stay (LOS), cost of hospitalization and NI such as bloodstream infections due to central venous catheters (BI), bacteremia, ventilator-associated pneumonia (VAP), and clostridium difficile (CDI) infection among patients with and without mechanical circulatory support (MCS) use (intra-aortic balloon pump [IABP], Impella/TandemHeart [PVAD], and extra corporeal membrane oxygenation [ECMO]) were analyzed. We identified 172486 cases of STEMI-CS, of which 53% required MCS. Among STEMI-CS cases 6104 (3.5%) developed NI and 3977 cases required MCS. The rates of NI were increased among patients with MCS (p<0.001, Table 1) with the highest rates encountered among patients with combinations of MCS. BI and CDI were higher in patients requiring ECMO whereas bacteremia and VAP were higher among patients requiring combined MCS (Table 1). Patients with STEMI-CS requiring MCS had higher rates of mortality, AKI, LOS and cost. However, among STEMI-CS patients the occurrence of NI was associated with lower incidence of in-hospital mortality in the subgroups of those requiring MCS, IABP, PVADs and combined MCS but no effect on mortality among those requiring ECMO(Table2). Patients with or without need for MCS and NI had significantly higher rates of AKI, longer LOS and costs (Table 2). NI are more frequent among patients with STEMI-CS requiring MCS and are associated with increased rates of AKI, LOS, and costs, but do not affect in-hospital mortality.