Renal Transplantation(RT) in patients with end-stage renal disease can improves survival rates and quality of life. Despite the benefits of immunosupressive medications in improving graft survival, they may have adverse effects such as development of neoplasms in transplant recipients. Post Transplatation Lymphoproliferative Disorders (PTLD) however is not uncommon complication after renal transplantation; we conducted a study to evaluate patients with PTLD. We enrolled 2117 RT recipients from jun 1984 to Mar2004 in order to finding evidences of neoplasms in pathological and clinical findings and data from patients with PTLD among them was reviewed illustratively. All exept two patient with PTLD were treated with cyclosporine. There was 46 RT recipients with different types of Neoplasms among those the most common types were skin neoplasms (24 cases; kaposi’s sarcoma 15 cases) and PTLD (14 cases, 30.4%). Mean (±SD) Age of PTLD patients at the time of transplantation was 37.86±9.67 years and 42.8 percent were females. Median and mean(±SD) time from RT to PTLD diagnosis were 38.5 and 50.35±41.7 months, respectively (from 1 to 146 months). Types of PTLD in these patients were: kidney (14.3%); GI (14.3%), Brain, Tonsils, palatine, Hodjkin’s, Large cell Lymphoma and ALL (each one 7.1%) and 28.6% indefined as unspecefic type. The one,five and ten year patients survival after transplantation were 71.4, 51.4, 44.3 percent respectively. Despite discontinueing immunosuppresive therapy of PTLD patients among survived patients over the time (6 of 14), in 5 survived patients, the graft was active up to mean time of 105.4±57.6 months after transplantation. Our findings showed that the prevalence of PTLD after RT is 0.66 percent, less than other reports of western contries. The fact that there was survived grafts despite discontinueing the immunosuppresive therapy up to a considerable time is of importance to notify.