Nosocomial meningitis is an uncommon complication of neurosurgical procedures, although nosocomial Gram-negative bacillary meningitis does occur occasionally in neurosurgical intensive care units (NSICUs). Acinetobacter baumannii is a rare cause of nosocomial meningitis, and is an even rarer cause of meningitis outbreaks in NSICUs. We report two cases of A. baumannii meningitis in an NSICU due to suboptimal aseptic technique in obtaining cerebrospinal fluid (CSF) specimens. After institution of infection control measures, i.e. aseptically collecting CSF specimens from distal external ventricular drain ports, there were no further cases. This report also reviews nosocomial Acinetobacter meningitis in adult neurosurgical patients.