The aim of this work was to provide a protocol of the necropsy technique in large animals, considering the collection, packaging and shipment of samples to complementary laboratories. Although the necropsy is the post-mortem examination of an animal, the best sample for the diagnosis of veterinary pathology, when available, is the living animal that is dying, that is, an animal in a terminal state of desease. The necropsy technique is accompanied by the correct description of the macroscopic lesions, the collection, conservation and adequate packaging of the samples for shipment to the laboratories. Together, the steps of necropsy and timely referral of the samples will be useful to build a definitive diagnosis of the cause of the animal's illness and/or death or any health problem of the herd. In conclusion, necropsy together with histopathology analysis and complementary laboratory tests are useful and necessary tools to establish the definitive diagnosis of disease or death in an animal or group of production animals.