A variety of tumors can occur with increased frequency in transplant recipients. This is related to the immunosuppressed status of transplant patients, which results in de novo malignancies. The possibility of inadvertent transmission of a maliganancy with the allograft is small, but nor negligible. The authors present a case of a 71-years-old patient who died 15 months after a renal transplant, with disseminated metastases of malignant melanoma. The human leukoyteantigenie profiles of the tumor, the kidney transplant, and the recipient's show an increased incidence of malignant melanoma and increased reactivationof dormant foci from pre-existing tumors Malignant melanoma is the most common tumor inadvertently transmitted through transplantation. Molecular analysis of tumor, allograft, and recipient tissues is the only reliable method for a definitive diagnosis of tumor origin.