Histoplasma meningitis (HM) has been reported to occur primarily in association with disseminated histoplasmosis (DH). We report a case of histoplasma meningitis occurring in a patient with common variable hypogammaglobulinemia (CVH) in which no manifestations of DH were observed. L. L., a 66-year-old Caucasian male, clerical worker, developed occasional episodes of dizziness and tinnitus in mid-1971. During 1972, increasing frequency of these episodes and gradually progressive confusion were noted. In January 1973, vomiting, forther confusion, obnubilation, and a left central facial paresis developed and he was hospitalized. Physical examination revealed no pulmonary abnormalities, lymphadenopathy or hepatosplenomegaly. Over the ensuing 6-week evaluation, there was occasional fever to 38.5 degrees C. Chest roentgenogram was normal. Cerebral angiography suggested a mass in the left cerebellar hemisphere. EEG was diffusely slow. Multiple CSF examinations revealed: Glucose 7-18 mg/with a normal blood glucose, protein 109-256 mg/and cells 66-140 (95 + % mononuclear). Histoplasma capsulatum was cultured from CSF but not from sputum, urine, blood or bone marrow. Skin tests for PPD, histoplasmosis, coccidiodomycosis, blastomycosis, mumps, dinitrochlorobenzene and streptokinase-streptodornase were negative then and 6 months later. Histoplasma serum antibody was absent. Immunoglobulin analysis revealed IgG 430 mg %, IgA 46 mg %, and IgM 35 mg %, which with the history and skin test results suggested CVH. Treatment with 2.51 gm of amphotericin B given intravenously over a 3-month period resulted in complete reversal of all neurologic signs and clearing of the confusion. The remission has been maintained for two years. This case represents a primary infection of the CNS by histoplasma. The relationship between the HM and the CVH will be discussed.