The frequency of malignancy in renal transplant recipients is much higher than in general population. Long-term immunosuppression and loss of immunologic surveillance over the neoplastic cells enhance the development of malignancy. The aim of the study was to investigate the occurrence of de novo neoplasms in renal transplant recipients according to immunosuppressive regimen and timeaftertransplantation. The study included 2600 consecutive renal transplanted patients between 1984-2006, regardless of their graft function. The 2600 patients who underwent renal transplantation in more than 20 years had a men follow up of 1-254 months (mean 55±52) Malignancy occurred in 56 patients (2.2%). The most common malignancies were lymphoma and post transplant lymphoproliferative disease (PTLD) (30.4) Kaposi sarcoma (28.6%), squamous cell carcinoma (12.5%) basal cell carcinoma (5.4%) melanoma and breast cancer (each 3.6%). Malignancies occurred in 32 (1.7%) of patients who had normal kidney function and in 8 (1.7%) of those who underwent dialysis after transplantation. Although Kaposi sarcoma was the most common malignancy after transplantation in our previous study, it seems that long term follow up of patients and improvement in patients and graft survival makes the PTLD the most common malignancy among them.