BACKGROUND We aimed to characterize the clinical manifestations and outcomes of patients with Acinetobacter baumannii bacteremia in the neonatal intensive care unit (NICU). METHODS All patients with A baumannii bacteremia in our NICU from 2004 to 2010 were reviewed. A matched case-control study was performed by comparing each case of A baumannii to 2 uninfected controls and all cases of Escherichia coli and Klebsiella bacteremia, respectively. RESULTS Thirty-seven cases with A baumannii bacteremia were identified. Multidrug-resistant isolate was noted in only 2 cases (5.4%), and the overall mortality rate was 8.1%. Compared with matched, uninfected controls, infants with A baumannii were more likely to have had a central vascular catheter (CVC) (P = .009), use of total parenteral nutrition (TPN) (P = .021), longer duration of ventilator use (P = .002), and hospitalization (P = .010). Compared with E coli or Klebsiella bacteremia, infants with A baumannii bacteremia had lower birth weight (median of 1,090 g vs 1,300 g, P = .044) and a higher rate of CVC and TPN use (both P < .001) at the time of infection. CONCLUSIONS A baumannii bacteremia occurs endemically or sporadically in the NICU, primarily in low-birth-weight infants on TPN use and with CVC in situ. Although A baumannii does not often cause mortality, and multidrug-resistant A baumannii is uncommon, it contributes significantly to longer hospitalization.