Background: The use of technology in distance education can help cross the borders of space and time for lifelong learning. One of the active learning methods is the use of the mobile apps with the potential to develop medical education. Objectives: The aim of this study was to evaluate the efficacy of using diabetes educational mobile app in the endocrine physiology virtual classroom during the COVID-19 pandemic. Methods: In the present study, an educational mobile app for diabetes, including the information modules, as well as educational videos made by the researchers of this study, was designed for 32 medical students of Abadan University of Medical Sciences who had endocrine physiology courses in the first semester of the academic year 2019 - 2021. A researcher-made questionnaire consisting of 10 questions about learning the educational content of diabetes through the application containing educational videos in the virtual classroom of endocrine physiology, scoring based on a five-point Likert scale, was provided. The data were analyzed by SPSS 21 using descriptive statistics. Results: The results obtained based on the highest satisfaction percentage were as follows: creativity in learning (90.625%), fast learning (87.5%), accessible learning (84.375%), practical learning (81.25%), sustainable learning (81.25%), eagerness to learn (78.78%), attractive learning (78.125%), accurate learning (78.125%), reducing the student's dependence on the teacher (75%), and feeling more confident (75%). Conclusions: Using educational applications along with other teaching methods can lead to fast, creative, practical, accurate, and lasting learning, and due to its attractiveness, it creates a desire to learn in people.