The human immunodeficiency virus (HIV) type 1 is the retrovirus which is responsible for the human immunodeficiency syndrome (AIDS) described in infancy in 1983. It is the most serious disorder caused by HIV, by a neurotropic virus, and is particularly severe in infancy. In children infected by vertical transmission of HIV, there is a shorter clinical latent period than in adults, and more viraemia than in children over the age of three months infected by blood transfusion. The neurological disorder caused by HIV is a complex clinical syndrome in which there may be varying degrees of retardation of cognition, movement or behaviour. A growing number of HIV+ children are being followed-up in the Hospital de Clinicas de Porto Alegre (HCPA) to treat the neuropsychomotor development and the presence of neurological behaviour in these children. The neurological, analytical (laboratory), electro-encephalographic and tomographic changes seen in a sample of 344 HIV+ children were studied. Analysis of these results showed a significant difference between affected and non-affected children. Encephalopathy occurred in 36% of the cases, being progressive in 29% and static in 17%. There was a relationship between neurological involvement at the first consultation and progress to encephalopathy. The RDNPM showed a tendency towards encephalopathy, usually between 1 and 5 years of age, which might also be the first sign of the disease. We found a significant relationship between being infected and having alterations not seen in cerebrospinal fluid, EEG, TCC and neurological progress.