Despite significant advances in antiretroviral treatment (ARV) and HIV infection prevention, about 400 children worldwide are still diagnosed daily with HIV infection, most cases due to perinatal transmission. It is estimated that the knowledge and rigorous application of prophylactic measures to reduce the vertical transmission of infection would significantly reduce this risk to less than 1%. We report the case of a 5 months old infant coming from a pregnancy with HIV risk and multiple risk factors for transmission of the vertical infection, who did not receive postnatal testing and treatment. The diagnosis was established during infancy, falling into the AIDS stage by cytomegalovirus (CMV) disease with retinal sequelae occlusion. ARV treatment was initiated late, but from the moment of diagnosis, requiring further changes due to drug interactions, lack of availability and resistance to TARV. Although the patient’s progression was marked by severe comorbidities: sequelae of CMV disease, mixed HIV and CMV encephalopathy, pulmonary tuberculosis, repetitive respiratory and digestive opportunistic infections, the evolution of immunological parameters was slowly favorable under treatment. Proper implementation of prophylactic measures in the newborn and the pregnant woman could have significantly reduced the risk of HIV transmission to the patient, with a high probability that she would not have been infected. The case reported reflects the failure of strategies to prevent HIV / AIDS infection in pregnant women and newborns; conclusions must be drawn to avoid similar situations. [ABSTRACT FROM AUTHOR]