The paper describes cases of disseminated small-cell carcinoma after kidney transplantation from a deceased donor to two patients. Microscopic examination showed that the kidney graft tumor consisted of tightly packed small rounded cells with hyperchromatic nuclei and a narrow cytoplasmic rim with invisible nucleoli. The mitotic index was 25—40/2 mm2. Azzopardi’s phenomenon and crush artifact were detected in the tumor. Giant cell and large cell components were 30—40% of the area of sections. Immunohistochemical examination revealed the expression of synaptophysin, chromogranin A, CD56, TTF-1, HMWK, СК7, СК18, and Ki-67 (80% of tumor cells). Histological findings and immunophenotype in both cases led to the conclusion about combined small cell carcinoma with renal graft involvement. Both patients died from tumor dissemination 9 and 11 months after transplantations. In reviewing the literature, the authors found only one such observation.