The Tuberculosis Working Group of the Portuguese Society of Pulmonology, feeling the need to develop guidelines for the diagnosis and treatment of latent tuberculosis infection, compiled a set of recommendations, in view to standardize procedures on this area. This document was prepared in collaboration with the Portuguese Societies of Internal Medicine, Pediatrics and Infectious Diseases, A review and update of guidelines for tracing and treatment of latent tuberculosis infection was made, concerning immunocompetent children and adults, as well as immunocompromised children and adults due to HIV infection. It is understood that these guidelines are to be used as general recommendations, and they should not replace the individual analysis of each case.