ABSTRACT Introduction The interpretation of the electrocardiogram (ECG) is fundamental for the identification of cardiovascular diseases, which are among the main causes of death in the world. The acquisition of this competence is essential in the training of the general practitioner and the use of new teaching tools, based on technology such as the use of mobile learning, can facilitate the acquisition of this knowledge. Objectives The objective of this study was to develop and evaluate the usability and the potentiality for the use in medical education of a mobile teaching application for ECG interpretation. Methods With the participation of two health professors and a computer scientist, a systems analyst, a programmer and a graphic designer, a mobile application was developed to teach ECG interpretation using the Java language. For validation analysis, a usability evaluation questionnaire based on the System Usability Scale (SUS) and a questionnaire used to evaluate the suitability of software for use in medical education, previously translated into Portuguese and applied in Brazil, were used. Results The “ECG Fácil” application was developed for off-line use and free access on iOS and Android platforms. In the validation phase of the application, a total of 109 students had free access to the mobile application for 6 weeks and then evaluated usability through a SUS-based questionnaire. The answers to the questionnaire showed good reliability, according to the validation analysis by Cronbach’s alpha coefficient (value: 0.74), and the application presented an excellent acceptance with a mean score on the SUS scale of 85.3. Meanwhile, fifteen faculty members evaluated the application through the questionnaire used to assess the suitability of software for use in medical education, with most agreeing with items indicating that it is suitable for use in medical education. Conclusion The “ECG Fácil” application was considered to be of good usability by students and suitable for educational purpose by teachers. Future studies with this application will be needed to assess the acquisition and retention of knowledge about ECG interpretation by students.