The most common histological type of retroperitoneal sarcomasis liposarcoma. Renal papillary cancers account for approximately10% of all known renal cell cancers and nephrectomy is thepreferred choice for the treatment in suitable cases. In this report,we presented a concurrency of giant retroperitoneal liposarcomaand renal papillary cancer in a 61-year-old male patient. He wasreferred to our clinic with complaints of abdominal distensionand pain. Computed tomography (CT) scan, magnetic resonanceimaging (MRI) and positron emission tomography-computedtomography (PET-CT) revealed a giant mass filling intraabdominaland retroperitoneal space, approximately 50x30 cm in size and alsoa separate mass which is 6x8 cm in size in the upper pole of the leftkidney. The giant mass was excised in two separate pieces. Afterfrozen section procedure, nephrectomy was performed for massarising from the left kidney. Histopathological analysis of the largemasses, revealed dedifferentiated liposarcoma and renal papillarycellular cancer in the abdomen and left kidney, respectively.In conclusion, a second primary tumor can be seen in patientswith giant retroperitoneal liposarcoma and coincidence ofthese tumors must be determined in the preoperative period forappropriate treatment.