INTRODUCTION:A study was conducted to evaluate the efficacy of antibiotic prophylaxis for early onset pneumonia in cardiac arrest patients who achieve return of spontaneous circulation (ROSC) and receive targeted temperature management (TTM). METHODS:A single-center, retrospective review was conducted using data collected from electronic medical records and pharmacy surveillance system at a 532-bed community medical center in adult cardiac arrest patients admitted to a critical care unit after ROSC and initiated on TTM between January 1, 2018 to July 31, 2020. The primary outcome was the incidence of early onset pneumonia defined as pneumonia occurring within the first seven days after cardiac arrest. Secondary outcomes include length of ICU stay, length of hospital stay, ventilator days, mortality at day 28, and incidence of subsequent C. difficile and other infections.