The United Kingdom and the United States successfully use polygraph examinations for assessment of progress of therapy and the risk of relapse among perpetrators of sex crimes, while in Poland the area is practically unknown. The work presents the four main directions of such studies, namely: examination of the past sexual behaviours, studies monitoring the presence of risky behaviours, examinations sustaining means of probation, and studies of specific questions. The article presents the benefits of such examinations and the factors necessary for such examinations to be therapeutically useful.