Background: There are few instruments to evaluate teachers' performance during medical residency in Spanish. Aim: To determine the validity and reliability of the MEDUC-PG14 instrument to evaluate teaching performance in the medical residency programs of the Faculty of Medicine, Universidad Peruana Cayetano Heredia (UPCH). Material and Methods: An open question about positive aspects that characterize a good teacher was added to the MEDUC-PG14 questionnaire. A pilot test was carried out with 15 residents to assess the correct comprehension of each question and carry out necessary changes. Subsequently, the instrument was sent by email to 366 residents of the UPCH Department of Medical Clinics. The reliability of the instrument was evaluated using Cronbach's Alpha. Construct validity was assessed by factor analysis, and the validity of content by a qualitative analysis of the answers to the open question added. Results: Seventy residents answered the questionnaire evaluating 46 teachers. Each resident evaluated one teacher. The factor analysis showed two dimensions explaining 83% of the variance: The dimension "Teaching and Evaluation" (11 items) and the dimension "Respectful Behavior" (three items). The global Cronbach's Alpha was 0.97 (0.97 for the Teaching Dimension 0.96 and for the Behavioral Dimension). The concept of "professional competence as a medical specialist" was rescued from the responses to the open question. Conclusions: The MEDUC-PG14 is an instrument with valid and highly reliable results. It is useful and easy to apply to evaluate teaching performance in postgraduate studies. Its use is recommended in residency programs of Spanish-speaking countries. However, the inclusion of an item referring to the professional competence of the teacher is suggested