It is reported in this article the use of stimulation with magnetic fields as a coadjuvant for the management of a case of delayed union of fracture in a polytraumatized mestizo canine that presented fractures of the femur and humerus. The magnetic field or magnetic therapy is an alternative for the management of complications in the reparative process of the fracture such as delayed union, non-union and poor union of the fracture. It is a non-invasive technique that has effects on the osteogenic and reparative activity of the bone tissue, favoring the reparative process both bone and biomechanical and avoiding maneuvers such as surgical reoperation. The response of the bone reparative process to therapy with stimulation with magnetic fields was considered beneficial.