Solid organ transplantation is currently the treatment of choice for renal, heart, and pancreas insufficiency and selected bowel diseases. Thanks to advances in medical technology, the lifespan of transplanted organs is currently about 10 years. To prevent graft rejection, patients need to take immunosuppressive drugs, usually for the rest of their Lives. Pathologists play a crucial role in organ transplantation. They are responsible for recognizing allograft rejection, both acute and chronic, differentiating rejection from drug toxicity, and identifying recurrent disease. In addition, pathologists identify new diseases in the graft, opportunistic infections in the transplanted organ or other organs, and the development of malignant tumors, which are more common in immunocompromised patients. Accordingly, transplant pathologists require a wide range of knowledge in many complex laboratory techniques, such as immunofluorescence, electron microscopy, immunohistochemical analysis, and molecular pathology. These tests are performed in dedicated Laboratories in departments of pathology. TranspLant pathology is an inseparable part of the field of transplantation medicine and greatly assists clinicians in the diagnosis of disease processes in transplanted organs and in the selection of appropriate treatment.