Although disseminated histoplasmosis is a common opportunistic infection in HIV patients in endemic areas, it is not widely known in Japan. We report a rare case of a man from Ghana infected with HIV who was hospitalized in Japan and who suffered from coinfection with cerebral toxoplasmosis and disseminated histoplasmosis. The diagnosis of cerebral toxoplasmosis was confirmed by a brain biopsy, and the therapy for the disease resulted in almost complete resolution of the brain lesion. However, fever of unknown origin continued for 2 weeks, and disseminated histoplasmosis was diagnosed by examination of a blood smear and by the detection of the histoplasma genome in the peripheral blood by means of polymerase chain reaction. The isolate was confirmed to be Histoplasma capsulatum var. duboisii. Therapy with amphotericin B was initiated, and no histoplasma genome in the peripheral blood was detected 3 days later. Unfortunately, the patient died after 10 days from acute respiratory syndrome. This case highlights that histoplasmosis should be included in the differential diagnosis of opportunistic infections in AIDS patients when patients have a history of travel to or arrival from endemic areas.