The overall goals of this study are to qualify the occurrence of Sexually Transmitted Infections (STIs) and Blood Borne Infections (BBIs) among the inmates in the Prison State System of the State of Guanajuato, Mexico, investigate their associated behavioral risk factors and to explore the context under which these behavioral risk factos occur. To achieve our goals, we will use a mixed methods research approach using both qualitative and quantitative methods. The study population is all adult incarcerated in the Prison State System of the State of Guanajuato, Mexico, and the prison's staffs. In an informal formative phase, we will collect information on the physical, social, economic, and policy environment in each one of the prisons using qualitative collection methods. Then, in a second quantitative phase, we will offer all inmates counseling for STIs and BBIs and tests for HIV, VHB, VHC, and syphilis, and applied a structured questionnaire to all consenting inmates, inquiring about practices related to the most relevant behavioral risk factors among inmates (sexual behavior, tattooing, and drug use), characteristics of the physical environment influencing these, knowledge about methods of transmission for HIV, and about human rights violations related to the right to health. In a third pahse, we will use regression methods to investigate individual and environmental level frisk factors for HCV, and for unsafe sex among detainees, and the use of qualitative information to provide explanations and contextualize the quantitative results.