A woman in Argentina may represent a unique case of posttreatment control of HIV after stopping antiretroviral therapy. Now in her late 50s, the woman was diagnosed with HIV in 1996 after developing wasting syndrome and toxoplasmosis. She started an early combination regimen, which was modified several times. In 2007, she stopped treatment entirely due to side effects, but her viral load has remained suppressed ever since, and she continues to maintain a normal CD4 count. Intensive testing revealed that her blood plasma viral load was below the limit of detection of the most sensitive tests, and HIV RNA was not detected in lymph node or gut biopsies. HIV DNA—the form of genetic material in the viral reservoir—was not detected in immune cells in the blood or in gut tissue but was present at a very low level in lymph node tissue. The woman shows only weak HIV-specific CD8 T-cell responses and no longer tests positive for HIV antibodies, suggesting she doesn’t harbor enough virus to trigger an ongoing immune response.