Objective: To evaluate the quality of root canal filling performed by undergraduate students in dental school at a private university in Lima, during the period 2011-2013. Methods: We performed a compilation of all periapical radiographs of patients with root canal treatment performed by undergraduate students of a private college of Dentistry in Lima, in the period 2011-2013 according to the selection criteria. The sample consisted of 501 root canals evaluated radiographically. We assessed the quality of the seal from the criteria proposed by Barrieshi-Nusair that measures the length and density of seals and other variables such as the location of the tooth, the gender of the students, clinic studied (course of study) and common mistakes during endodontic treatment. We performed chi-square test to establish the associations of the study variables. Results: With regard to quality, it was...