Promoting quality of life, combined with the prevention of diseases and accidents in the workplace, is one of the purposes of ergonomics. In this context, cashiers perform a work activity with a high rate of ergonomic risks due to injuries related mainly to repetitive tasks and exhausting postures for long periods. Based on this scenario, an investigation was carried out, through a systematic theoretical-empirical methodological approach, regarding the ergonomic evaluation with a focus on the biomechanical research of the repetitive movements of supermarket cashiers. For this purpose, the research was based on a case study in a supermarket in the city of Belém - Pará/Brazil. Thus, the objective of the localized work is the biomechanical investigation of the repetitive movements observed during the performance of microtasks required in the performance of the work activity. The investigation was carried out using the Kinovea program, and the results obtained allowed highlighting the angular variables from the cinematographic study of the shoulder, elbow and wrist joints. In this way, it contributes to demonstrating the risks and suggestions and recommendations in order to prevent long-term injuries, in addition, it provides theoretical basis on the working conditions of the group under study.