RESUMO
Necropsy is the postmortem examination of an animal's body. Experiments on laboratory animals are performed to gather scientific data relevant to basic and, even more often, translational research, mainly in the field of translational medicine. A necropsy conducted on laboratory animals subjected to experimental research provides an opportunity to exhaustively explore pathological processes that took place during life. In order to achieve that goal, procedures of biomaterial collection should be performed timely, bearing in mind the inevitable process of postmortem tissue decay, and precisely, to avoid mechanical tissue damage.In this chapter, procedures of collecting organs and tissue in a way that ensures the preservation of the organ structure, tissue organization, morphological characteristics of cells, and last but not least, intracellular protein and nucleic acid content and chromosome organization are going to be described step by step.