Histoplasmosis caused by the fungus Histoplasma capsulatum subtype capsulatum is often lethal in patients with AIDS. Urine antigen testing is highly sensitive and much quicker for diagnosis than culture; skin or bone marrow biopsy and polymerase chain reaction are alternative rapid diagnostic methods. Histoplasmosis is well documented in the Americas, but less well known elsewhere, partly because it has a patchy and incompletely appreciated distribution around the world. The geographical epidemiology of histoplasmosis in South East Asia is underdeveloped. We conducted a systematic literature review of cases of all disease forms of histoplasmosis in South East Asia, not including the Indian sub-continent. We also reviewed all histoplasmin skin test mapping studies to determine localities of exposure. We found a total of 407 cases contracted or likely to have been contracted in South East Asia. Numbers of cases by country varied: Thailand (233), Malaysia (76), Indonesia (48) and Singapore (21), with few or no cases reported in other countries. Most cases (255 (63%)) were disseminated histoplasmosis and 177 (43%) cases were HIV associated. Areas of high histoplasmin skin test sensitivity prevalence were found in Myanmar, the Philippines, Indonesia, Thailand and Vietnam - 86.4%, 26.0%, 63.6%, 36.0% and 33.7% respectively. We have drawn maps of these data. Histoplasmosis is endemic in multiple regions within South East Asia and further study is required to ascertain the extent of this. Diagnostic capability for patients with HIV infection is urgently required in South East Asia, to reduce mortality and mis-diagnosis as tuberculosis.