Introduction Total (or near-total) thyroidectomy followed by TSH-stimulated administration of large activities of 131-iodine (131I) is the treatment of choice for DTC [1-3]. The serum thyroglobulin (Tg) measurement during hypothyroidism, just before radioiodine thyroid ablation, has proved to be effective for predicting persistent/recurrent disease [4-8]. Recently recombinant human TSH (rhTSH) showed to be safely employed instead of thyroxine (T4) withdrawal (offT4) to prepare patients for radioiodine ablation [9-10]. However, the Tg level are measured 48 hours after radioiodine administration when rhTSH is used as stimulation [11]. Consequently, due to the radioiodine-induced thyroid cells damage and Tg release, the Tg measurement would not have reliable predictive value in patients treated by rhTSH stimulation [12]. The present study was undertaken to evaluate if preablativeTg measurement under T4 treatment is of prognostic value and serves as surrogate marker of offT4-stimulated preablative Tg.