Hyperfunctional nodular goitre is the most common thyroid non-neoplastic condition in endemic areas. Iodotherapy is the basic method in thyroid gland hyperfunction treatment. The aim of the study was to evaluate proliferation of thyroid follicular cells in nodular goitre after iodotherapy. The study was carried out on 32 women, 30-76 years old. Cytological and immunohistochemical evaluations were based on the material, obtained by Fine-Needle Aspiration Biopsy (FNAB). Proliferative activity was immunohistochemically assessed. The influence of radioiodine on thyroid follicular cells was evaluated as a difference between the proliferation of follicular cells before and after its application. It was concluded that the proliferative activity of thyroid follicular cells decreased considerably after radioiodine therapy.