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Introduction Thyroglobulin (Tg), the most common marker to determine remission of differentiated thyroid carcinoma ( DTC), can take 18 months or longer to be undetectable. We hypothesized that Tg stimulated after surgery and immediately before radioiodine treatment (baseline-stimulated Tg) could be a good predictor of remission at 18-24 months. The aim of this study was to evaluate the role of baseline-stimulated Tg as early prognostic marker of DTC. Patients and methods Retrospective study of 133 patients with DTC from 1998 to 2010 (age at diagnosis 47·4 ± 16·8, follow-up 5·09 ± 3·2 years). Initial subset analysis was performed after excluding patients with positive TgAb, who were later included in the second. Baseline-stimulated Tg was divided into tertiles. Multivariate logistic regression analysis included baseline Tg and other known prognostic markers and receiver operating characteristic ( ROC) curve to identify the best cut-off level of baseline Tg were performed. Results Baseline-stimulated Tg in the highest tertile was the only predictive variable of persistence of disease at 18-24 months in the initial analysis ( OR 45·3, P < 0·01). In the second analysis, the predictive variables were baseline-stimulated Tg ( OR 39·6, P < 0·001), presence of TgAb ( OR 23·4, P < 0·005) and uptake outside of the thyroid bed post-treatment whole body scan ( WBS; OR 5·3, P < 0·05) were predictive of persistence of disease. The ROC curve showed that baseline-stimulated Tg below 8·55 μg/l identified 95% of disease-free patients at 18-24 months after initial treatment. Conclusions Baseline-stimulated Tg is a good predictor of remission of disease at 18-24 months after initial treatment and could be a useful marker to stratify risk immediately after surgery. [ABSTRACT FROM AUTHOR]