Purpose: Survival rate after renal transplantation has increased after intense immunosuppressive agents and sophisticated operative techniques were introduced, but incidences of malignancy increase with time after transplantation. Methods: We reviewed our experiences about post-transplant malignancy in patients who received renal allografts in our hospital from January 1981 to December 1999. The incidences and types of malignancy were analysed in 241 renal allograft recipients, who were followed-up for 1265 patient-years. Results: Seven malignancies were found in 241 patients (2.9%). The mean age of these patients at diagnosis of malignancy was 45.5 years and the average interval between transplantation and diagnosis of malignancy was 34.9 (9.S-71.6) months. The types of malignancy were non-Hodgkin`s lymphoma (n=2; CNS and nasal cavity), colon cancer with metastasis (n=2), in situ carcinoma of uterine cervix (n=1), follicular carcinoma of thyroid (n=1) and transitional cell carcinoma of bladder (n=1). Surgical resection was performed in 5 patients and 2 of them developed distant metastasis during follow-up periods. Radiotherapy was performed in 2 patients with non-Hodgkins lymphoma and 1 patient with cord compression due to vertebral metastasis. Four patients are now alive and 3 of them have functioning renal allografts. Conclusion: We reviewed the incidences and types of post-transplant malignancy in our center and concluded that regular screening for malignancy and meticulous diagnostic approach for suspected symptoms ar signs are important to immunosuppressed renal allograft recipients.