Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 59 12 2021 12 15 699 703 Hossein Hemmati Department of Vascular Surgery, Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran Behrang Motamed Department of Internal Medicine, Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran Mehdi Pursafar Department of General Surgery, Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran Mohaya Farzin Department of Physiology, Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran Zakiyeh Jafaryparvar School of Nursing and Midwifery, Nursing and Midwifery Care Research Center, Tehran University of Medical Sciences, Tehran, Iran Mohammad Sadegh Esmaeili Delshad Department of Vascular Surgery, Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran Pirooz Samidoost Department of General Surgery, Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran Elahe Rafiei Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran Soudabeh Bahush Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran 2021 02 16 2021 08 10 Vitamin D plays a crucial role in calcium metabolism through the parathormone-dependent process. The deficiency of this important nutrient may be associated with hypocalcemia after thyroidectomy. To evaluate the role of vitamin D in predicting hypocalcemia following total thyroidectomy. In this study, sixty-two patients who underwent total thyroidectomy for benign or malignant thyroid disease were included in this prospective study. Preoperative vitamin D serum levels and parathormone (PTH) levels were determined. The association between preoperative vitamin D status and the development of hypocalcemia was investigated. In this study, 62 patients were evaluated. The mean age of the subjects was 47 years. Of the 62 patients studied, of which 9 were male patients (14.5%), and 53 were female (85.5%), the results of our study showed. In both groups with and without vitamin D deficiency, calcium levels decreased significantly (P=0.01). In our study, it was found that there was no significant relationship between postoperative hypocalcemia and vitamin D deficiency. (P=0.441). After reviewing the data and according to Spearman correlation statistical test, no significant relationship was observed between serum parathyroid hormone (PTH) and calcium after thyroidectomy (P=0.340). Vitamin D deficiency is a risk factor of hypocalcemia after total thyroidectomy for benign goiter. Although post thyroidectomy hypocalcemia is multifactorial, vitamin D deficiency, particularly severe form, is significantly associated with the development of biochemical and clinical hypocalcemia. Vitamin D supplementation can prevent this unwanted complication in such patients. https://acta.tums.ac.ir/index.php/acta/article/view/9167