ObjectiveTo investigate the clinical characteristics and antimicrobial resistance of Acinetobacter baumannii(A. baumannii) in neonatal intensive care units (NICUs). MethodsThe clinical isolation and antimicrobial resistance of A. baumannii causing healthcareassociated infection(HAI) in 4 NICUs of a hospital from October 2012 to October 2014 were analyzed statistically. Results A total of 11 640 neonates were admitted in 4 NICUs, 500(4.3%) developed HAI, 51(10.2%) developed 52 cases of A. baumannii infection. Distribution of A. baumannii infection was as follows: NICU of extremely premature infants, premature infants, fullterm infants，and surgical NICU were 42, 1, 4, and 5 cases respectively. Incidences of A. baumannii HAI in 4 seasons were compared, difference was statistically significant(χ2=16.05，P<0.05），infection mainly occurred in the spring and summer. A. baumannii had high resistance rates to βlactam antibiotics (such as piperacillin/sulbactam, cefepime, imipenem) and gentamycin（＞90%），resistance rate to amikacin was the lowest (51.9%). Among 52 strains of A. baumannii, 46 were multidrugresistant strains, and 3 were extensively drugresistant strains. ConclusionA. baumannii HAI is most serious in NICU of extremely premature infants, resistance rates to commonly used antimicrobial agents are high.