Thirty-one cases of post neurosurgical bacterial meningitis from one center were reviewed to determine their promoting factors and responsible organisms. Most cases occurred after a protracted operation (6 hours on average). 26% cases were related to a primary cutaneous infection. 58% organisms were Gram negative bacilli. The course of meningitis was often complicated or prolonged due to a scalp decubitus ulcer or cerebrospinal fluid leakage. Vancomycin is often requested during staphylococcal meningitis. Third generation cephalosporins have low MIC against many Gram negative bacilli and should be used. Pefloxacin, a new quinolone, may be valuable. Treatment of scalp wound infection is often requested.