Liver transplantation in patients with severe renal disfunction of the liver is the only form of therapy that can significantly extend the life expectancy of patients. The development of science in several areas contributed to the better results of liver transplantation procedure. Liver transplantation, as well as most of such radical operations, is leading to a series of complications of which the occurrence of malignant disease is one of the major causes of death among the patients. Malignant tumors in patients after liver transplantation ocurre due to the application of immunosuppression, viral infections, residual tumor cells ... Immunosuppression is an important part in therapy by protecting the allograft from rejection. As consequence there is a reduced possibility of the body to defend against infections and tumor cells. There are two forms of malignant diseases in patients that undergo immunosuppression ; newly tumors, and recurrence of the tumor. De novo tumors are defined as tumors arising in patients in whom there is no data from previous malignant diseases. They are divided into skin, lymphoproliferative, colorectal tumors. ----- Recurrence of the tumors is defined as the reocurrence of tumor cells that were present before transplantation. It can be developed in the transplanted organ, the peritoneal cavity, pelvic cavity, regional lymph nodes and /or distant metastases. The most common tumors are hepatocellular carcinomas, kolangiocelularni cancer, neuroendocrine tumors. ----- Due to the frequent incidence of tumors in patients with immunosuppression regular follow up in patients are required to reduce the mortality and reduce treatment costs of patients. In some cases retransplantation is required. Waiting lists are long, but there are interventions that increase the survival rates of patients while waiting a suitable donor.