Francis of Assisi (c. 1181–1226) is one of the most venerated religious figures in Roman Catholicism and one of the most depicted saints in art. The aim of this research is to highlight the presence of goiter in some depictions of the saint and to argue for the possible presence of this condition in Francis himself.

Four paintings that represent Francis of Assisi belonging to the period between the fifteenth and the seventeenth century were analyzed. Early biographies of the saint were examined.

In the analyzed paintings, the saint was represented with a throat swelling. Actually, early biographies do not support the hypothesis that Francis of Assisi suffered from goiter.

The choice to represent Francis of Assisi with a goiter could be a desire to emphasize the inadequacy of his diet and thus to highlight his pauperism. Even though thyroid-related symptoms were often described, the presence of thyroid goiter in Francis is not confirmed by biographies. However, it should be considered that the directives of the Franciscan Order pushed authors to show a figure of the idealized saint for purposes of religious education and have increasingly detached from his physical characteristics.