OBJECTIVE: The incidence of the acquired immunodeficiency syndrome (AIDS) has increased in Santa Catarina State in Brazil over the last years, with a high number of infected women and children. The purpose of this study was to establish the main characteristics of the children from this State whose HIV serologic tests were positive. METHODS: This was a descriptive study of 176 children with positive serologic tests to HIV, conducted in the Hospital Infantil Joana de Gusmão, Florianópolis City, Santa Catarina State, Brazil. RESULTS: Most of the children (105 cases, 59.6%) were born in Florianópolis, Capital of Santa Catarina State, and Itajaí (22 cases, 12.5%). Vertical transmission of HIV was observed in 167 patients (94.9%). Among 167 HIV-positive mothers, 77 (46.1%) of them acquired the virus by sexual transmission and 35 (21.0%) by use of injectable drugs. However, among 89 HIV-positive fathers, 63 (70.7%) of them used to take drugs. The average age of the HIV-positive children whose serologic tests became negative was 10.5 months. Among 103 symptomatic patients, 87 (84.5%) presented hepatomegaly, 81 (78.6%) lymphadenopathy, 66 (64.0%) splenomegaly, 59 (57.3%) skin bruises, 54 (52.4%) recurrent bronchopneumonia and 50 cases (48.5%) recurrent diarrhea. The most frequent opportunistic infection was mucocutaneous candidiasis that occurred in 41 children (39.8%). CONCLUSIONS: The characteristics were similar to those reported in the literature. A great concentration of HIV infected persons was observed in the coast area where there are three harbor towns, an elevated number of injectable drug users and presence of many tourists.