Between January 1999 and December 2003, 81 cases of single pathogen-related culture-proven Gram-negative adult bacterial meningitis were identified at Chang Gung Memorial Hospital-Kaohsiung. Of these 81 cases, Acinetobacter infection was found in 13 cases. Clinical and laboratory data of these Acinetobacter meningitis patients were studied and were compared with those of other 68 non-Acinetobacter Gram-negative bacterial meningitis (GNBM) patients. Of the 13 implicated Acinetobacter strains, A. baumannii was the most common (12), and the other was A. lwoffii (1). Eleven of these 13 cases were due to a post-neurosurgical infection. The results of the antibiotic susceptibility test of the 13 Acinetobacter strains from cerebrospinal fluid included ceftriaxone, (1/13, 8%), ciprofloaxin (6/13, 46%), ceftazidime (6/13, 46%), cefepime (7/13, 54%), ampicillin-subtactam (7/13, 54%), imipenem (12/13, 92%) and meropenem (12/13, 92%). One strain with pan-drug resistant A. baumannii (PDRAB) emerged in 2003. A statistically significant difference between Acinetobacter meningitis and non-Acinetobacter GNBM included hydrocephalus and ceftazidime-resistance. A mortality rate was 30% (4/13), and 7 of the other 9 survivals had severe neurologic deficits. The emergence of Acinetobacter infections in adult post-neurosurgical infections, multiple antibiotic resistant characteristics, and the emergence of PDRAB strain remained a challenge of the initial management of this specific meningitis. Use of carbapenem, especially meropenem, could be considered as one of the initial empiric antibiotics chosen for the management of adult post-neurosurgical meningitis.