We present a case of tuberculous meningitis in a patient with acute myelogenous leukemia. The patient was in complete remission; he had persistent lymphopenia and CD4+ T lymphocytopenia. Diagnosis was complicated by the chronic and subacute nature of symptoms; some originally thought to be secondary to depression and chemotherapy related toxicity. Treatment was further complicated by the unusual phenomenon of paradoxical progression of disease while on appropriate therapy. This case illustrates the importance of consideration of mycobacteriosis in the differential diagnosis of chronic unexplained fever complicating treatment for acute leukemia. The natural history and essential aspects of diagnosis and treatment of CNS tuberculosis are reviewed. The clinical significance of unexplained CD4+ T lymphocytopenia and chronic lymphopenia in patients with leukemia is also discussed.