Objective: To determine the prevalence of the lower third molar position according to the classification of Winter and the classification of Pell and Gregory in patients between 18-35 years of age of the Universidad Peruana de Ciencias Aplicadas Dental Clinic during the period from February 2011 to December 2012. Material and methods: This is an observational, descriptive, transversal and retrospective study in which 582 panoramic x-rays were selected of the clinical record of patients that were found in the range of age required and in the establish period of time. Results: 1067 lower third molars were evaluated. According to the study it was observed that the most prevalent positions, according to the classification of Winter were vertical (42, 3 %) and mesioangular (31, 4 %), for both male and female and in both sides for patients between 18 and 35 years. According to the classificati...