The shoulder is one of the most complex systems in the human body. To know how its work is essential to understand the biomechanics of the body. The purpose of this study was to analyze the influence of Local Coordinate Systems in the kinematic analysis of GlenoHumeral joint. The motion tracking was performed using passive sensors attached to pins. Trabecular pins were placed on the shoulder and scapula. The data processing was performed using the free open software pyFormex. The joint displacements were determined by two different variants of Coordinate Systems, being detected a difference from 2 to12 degrees