UNLABELLED Southern Brazil has the highest prevalence rate of AIDS in the country and is the only region in the Americas where HIV-1 subtype C prevails. OBJECTIVE We evaluated the epidemiologic and clinical characteristics of pregnant women living with HIV/AIDS in the South region of Santa Catarina, Brazil. METHODS All pregnant women with HIV infection attending the obstetric outpatient clinic of Criciúma, State of Santa Catarina, in 2007 (n = 46) were invited to participate. Data of 36 eligible participants were obtained through a standardized questionnaire. RESULTS The great majority were young, with a steady partner, low family income, low education level and referring early first sexual intercourse. Many reported use of illicit non-injecting drugs (55.5%) and unprotected sex with partners that were HIV-positive (57.7%), injecting drug user (22.2%), male inmate (19.4%), truck driver (13.8%), with history of sexually transmitted disease (11.1%) or men who have sex with men (MSM) (2.8%). Most (66.7%) of the participants had their HIV diagnosis done during the pregnancy, 7 (19.4%) had a previous history of HIV mother-to-child transmission. Therapy based on highly active antiretroviral therapy (94%) was initiated at 19.3 weeks on average and 33% showed irregular antiretroviral adherence. CONCLUSION These results confirm previous data on HIV epidemiology in Brazil and suggest that the women partners' sexual behavior and unprotected sexual intercourse are important aspects of HIV epidemic. Additional efforts in education, prophylaxis and medication adherence are needed.