The popularity of guinea pig in the role of exotic pets there is an increase for specialized veterinary services. In small mammals, limb fractures are a common occurrence following a fall from a height. Whenever possible the option of fracture repair should be considered and proposed to the owner. Fracture repair with external fixation and intramedullary pins has been described in small mammals, and local and regional anaesthetic techniques are widely accepted to provide good analgesia in rodents. The fracture surgery are not rare in guinea pigs, so the surgical repair is recommended in first treatment and give the highest successfully result. This paper reports the case of a complete fracture of the femur in a guinea pig treated surgically with an intramedullary pin.