We report a case of post-neurosurgical meningitis, subdural empyema, and cerebral abscess caused by multidrug-resistant Acinetobacter baumannii (MRAB) poorly susceptible to colistin. A 49-year-old man was transferred to our hospital after surgical treatment for putaminal hemorrhage in a foreign country hospital. Several examinations revealed surgical site infection (SSI). From cerebro-spinal fluid examination via ventricular drainage, MRAB was recovered. The minimum inhibitory concentration (MIC) of colistin was 2 µg/mL. Intravenous administration of colistin with ceftazidime and rifampicin was started, with intrathecal colistin administration, based on the results of a Break-point Checkerboard examination, and resulted in effective infection control. Nosocomial infection by MRAB has become an emergent problem in many countries. In Japan, several outbreak accidents caused by MRAB have been reported so far. In this case, genetic analysis revealed that the pathogen had originated from a foreign country, and the prevalence of colistin-resistant pathogens has also increased in these countries. Besides adequate isolation precautions, strategies for post-neurosurgical SSI management and establishment of effective treatments are necessary against neurosurgical SSIs caused by colistin-resistant MRAB.