Introduction To establish prevalence and identify risk factors for HIV, Syphilis, Hepatitis B and Hepatitis C infections in the Private Population of Freedom (PPF) in the ComplexoPenitenciário do Vale do Itajaí-Canhanduba, Itajaí, Santa catarina, Brazil.

Methods In the period between December of the year 2015 and August of the year 2016 a research was carried out at the Canhanduba penitentiary, Itajaí-SC, with quantitative and prospective character. The data collection was performed through a review of 921 medical records and rapid tests provided by the Ministry of Health - Brazil and the State Department of Health - SC. There were 655 interns participating initially, of these 170 did not want to be part of the research and 470 accepted to perform the tests.

Results The prevalence of infections in this population was 2.9% for HIV, 5.9% for Syphilis, 1.0 for HBV and 2.5% for HCV. This population were consisted of men, mostly in the age group between 20 and 40 years. It was possible to identify a high consumption of all kind of drugs in this population, being alcohol, marijuana and cocaine the most reported.

Conclusion In view of the observed aspects, it was possible to conclude that PPLF has a higher prevalence for infectious diseases when compared to the free population, since most of them present with a few years of studies, in use of illicit drugs and in activity unprotected sex. In addition to being exposed to a crowded environment, precarious and with a high turnover of people. The statistical data on this subject in Brazil are rare and out of date, thus not demonstrating the real epidemiological and serological situation of this population as a whole, so studies in several areas must be carried out in order to formulate new strategies of action.