Many HIV infected patients are at risk for HTLV-I co-infection worldwide. These patients exhibit abnormally highCD4+ T lymphocyte counts that are not a reliable parameter of the immune status. We report a HIV/HTLV co-infected patient who developed progressive multifocal leukoencephalopathy despite of a high CD4+ T lym-phocyte count emphasizing that this situation can be observed in regions around the world where HTLV-I infection is prevalent.2020-09-20