OBJECTIVE: This study aims to examine the use and safety of rifampin in the hospitalized infants. STUDY DESIGN: Observational study of clinical and laboratory adverse events among infants exposed to rifampin from 348 neonatal intensive care units managed by the Pediatrix Medical Group between 1997 and 2012. RESULT: Overall, 2,500 infants received 4,279 courses of rifampin; mean gestational age was 27 weeks (5th, 95th percentile; 23, 36) and mean birth weight was 1,125 g (515; 2,830). Thrombocytopenia (121/1,000 infant days) and conjugated hyperbilirubinemia (25/1,000 infant days) were the most common laboratory adverse events. The most common clinical adverse events were medical necrotizing enterocolitis (64/2,500 infants, 3%) and seizure (60/2,500 infants, 2%). CONCLUSION: The overall incidence of adverse events among infants receiving rifampin appears low; however, additional studies to further evaluate safety and dosing of rifampin in this population are needed.