It is well known fact, that most patients after thyroid lobectomy are euthyroid (60%-90%) and do not require thyroid hormone replacement therapy. However, it is an important question whether thyroid hormone administration postoperatively can prevent recurrent nodular thyroid disease in euthyroid hemithyroidectomized patients? The aim of the present randomized study was to compare the prevalence of recurrent nodular goiter in the contralateral thyroid lobe among patients after unilateral thyroid lobectomy for unilateral multinodular goiter (MNG) receiving versus not receiving prophylactic levothyroxine (LT4) treatment postoperatively in a five-year follow-up.