The different surgical chances for the treatment of non toxic nodular goiter led the Authors to study the residual function after partial thyroidectomy. A variable rate of recurrences and hormone deficiency was shown in patients who underwent sub-total thyroidectomy, lobectomy and enucleation. It depended on the amount of residual gland and the different methods they used. Recurrences occurred more in patients studied by ultrasonography. After sub-total thyroidectomy the Authors noted a more reduced number of recurrences than after lobectomy and enucleation. There was a meaningless connection between high plasmatic levels of TSH and recurrences. Subclinical hypothyroidism was higher in patients who underwent subtotal thyroidectomy than in patients treated with lobectomy and enucleation. These clinical data show that recurrences could depend on growth factors (EGF, IGF) in thyroid tissues and not only on TSH action. Therefore the surgical attitude of the authors in the treatment of nodular goiter consists in total thyroidectomy.