50 year old female patient who has headache, dizziness, and nausea-vomiting was admitted to neurosurgery clinic, and an image that was suggestive of an abscess was detected in the cerebellum by means of MRI (Magnetic resonance imaging). This cerebellar abscess was resected together with capsule by right paramedian suboccipital craniotomy, and ceftriaxone and metronidazole treatment was ordered empirically. In the microbiological examination by Gram stain, no micro-organisms were seen. Microorganism was detected on the anaerobic culture and was identified as B. fragilis. Metronidazole was susceptible according to the antibiotic susceptibility test results, so this treatment was continued. The patient was discharged by healing. In diagnosis and treatment of these kinds of patients, it should be considered that B. fragilis can be cause of abscess in the brain.