We report an 8 year-old girl with well-controlled perinatally acquired HIV infection who developed autoimmune type 1 diabetes mellitus (DM1A) confirmed by the presence of diabetes-related auto-antibodies. Although non-autoimmune insulin dependent diabetes mellitus (DM1B) and more frequently type 2 DM has been reported in patients affected with HIV, this is the first report of DM1A diagnosed in an HIV positive patient.