The real need to perform RRA is nowdays under debate in patients with low and intermediate risk PTC. Objective: To evaluate the diagnostic and therapeutic role of this procedure. Patients: We retrospectively analyzed 548 consecutive patients (pts) with PTC treated with total thyroidectomy, referred to our Institute in 2006 to perform RRA. All patients were treated in hypothyroidism with a standard activity of 30 mCi of 131I followed by a Whole Body Scan (pWBS). Serum thyroglobulin (Tg), thyroid hormones measurements and neck ultrasound were performed in all pts. We classified patients in two groups: low risk (LR; n=348) and intermediate risk (IR; n=200). Results: In addition to the thyroid remnant, the pWBS showed further areas of 131I uptake in 16/548 pts (2.9%): 7 LR (2.2%) and 9 IR (4.3%) (p=0.09). In 11/16 pts (4 LH, 7 IR) pWBS revealed latero-cervical lymph node metastases, 9 out of 11 were also detected by ultrasound followed by fine needle aspiration citology. The pWBS showed mediastinal uptake in 1/16 (1 IR), lung metastases in 3/16 (2 LR, 1 IR) and bone metastases in 1/16 (1 LR). Only 7/548 (1.3 %) (5 LR and 2 IR) metastases were detected by pWBS only. The mean value of serum Tg was 86.329+112.398 ng/ml in LR and 242.411+260.779 ng/ml in IR (p=0.1). At the end of follow-up (median 7.8 years), 8/16 pts were free of disease (5 LR, 3 IR) while the other 8 had persistent disease: 5 “biochemical” disease (1 lung and 4 lymph nodes) and 3 “structural” disease (1 bone, 1 mediastinum and 1 lymph node). Remission was achieved in 3 cases after one single 131I activity, in 1 case after surgical treatment and in the last 4 cases after several 131I courses . Conclusions: The pWBS after RRA played an important diagnostic role in only 7/548 (1.3 %) PTC pts with no difference between LR and IR groups. Serum Tg was unable to predict pWBS positive cases. Three out of 3 cases with lung and 8/11 lymph nodes metastases revealed by pWBS have been cured by 131-I. We do not know what could happen to these subjects, especially those with lung metastases, if 131I and pWBS were not performed.