Dematiaceous fungi have melanin-like pigment in the cell wall and usually cause a variety of dermal infections in humans. Infections of the central nervous system(cerebral phaeohyphomycosis)are rare but serious, since they commonly occur in immunocompromized patients. A 76-year-old man was admitted with mild motor aphasia and underwent total excision of a mass in the left frontal lobe. With the postoperative diagnosis of brain abscess due to infection with dematiaceous fungi (C. bantiana) associated with hypogammaglobulinemia following gastrectomy, intravenous antifungal drugs including amphotericin B and fluconazole were administered. Regrowth of the abscess with intraventricular rupture was noted at about the 88th day after the initial surgery, and the patient underwent neuroendoscopic aspiration of the pus and placement of a ventricular drain. Following intraventricular administration of miconazole through ventricular drainage or an Ommaya reservoir, neuroradiological findings improved, but general and neurological conditions worsened. Further treatment was discontinued and the patient died 9 months after onset. The poor outcome in this patient is attributed to 1)intractability of dematiaceous fungi, 2)development of ventriculitis and the need for intraventricular administration of antifungal drugs, and 3)untreatable hypogammaglobulinemia following gastrectomy.