The main advantage of organ‑sparing operations compared to thyroidectomy is the ability to maintain patients’ euthyroid status in the postoperative period. Predicting the development of postoperative hypothyroidism could contribute to individualizing the patient’s approach and help surgeons choose the optimal volume of the operation. Objective to investigate the relationship between an elevated antibody to thyroid peroxidase (TPO‑Ab) level at the preoperative stage and the development of hypothyroidism after organ‑sparing surgery on the thyroid gland. Materials and methods. In a monocenter retrospective study involving 61 patients who underwent surgery in the conditions of Ukrainian Scientific and Practical Center of Endocrine Surgery, transplantation of endocrine organs and tissues of Ministry of Health of Ukraine) from November 2022 to December 2023 in the volume of hemithyroidectomy with removal of the isthmus and pyramidal lobe, (if available), the levels of TPO‑Ab were determined at the preoperative stage. Depending on the TPO‑Ab value, patients were divided into 2 groups. The first group (n=17) consists of patients in whom an increase in TPO‑Ab level was detected relative to reference values. In the second group (n=44) patients an increase in TPO‑Ab level was not observed. The next stage was the determination of thyroid‑stimulating hormone and free thyroxine in the blood serum of patients 1 and 6 months after surgery. The number of patients with hypothyroidism in both groups was determined. Statistical processing of the results was performed. Results. In 27.9% of the total sample at the preoperative stage, an increased TPO‑Ab level was observed (group 1), in 72.1% of the total sample, TPO‑Ab was not increased (group 2). After surgery, hypothyroidism was detected in 9 patients of the first group (52.9%) and in 13 patients of the second group (29.5%). While the proportions of patients with and without hypothyroidism in group 1 do not differ significantly (52.9% and 47.1%, respectively), in group 2 the proportion of patients with hypothyroidism is considerably lower (29.5% versus 70.5%, p<0.01). A higher proportion of patients with postoperative hypothyroidism was demonstrated in group 1 compared to group 2. According to calculations, the probability of postoperative hypothyroidism in patients with elevated TPO‑Ab is almost 2.7 times higher (OR=2.683), but the level of reliability of this conclusion is p>0.05. The hypothesis about the existence of a relationship between the presence of elevated TPO‑Ab levels and the presence of postoperative hypothyroidism in this series of observations was not statistically confirmed. Patients with elevated TPO‑Ab levels had an almost 2.7 times greater likelihood of developing postoperative hypothyroidism. Conclusions. The probability of developing postoperative hypothyroidism is 2.7 times higher in the group of patients with elevated TPO‑Ab levels than in the group with normal TPO‑Ab levels, but this relationship is not statistically significant. Elevated TPO‑Ab levels in the preoperative stage are not a decisive factor in determining the extent of surgical intervention on the thyroid gland. However, given the presence of certain pronounced trends, it should be considered advisable to continue the research.