Background: Thyroid disorders are less common in men and can present at any age. According to reports, the majority of goiter treatments is thyroid surgery. Aim and objectives: This research's primary objective was to compare the incidence of post thyroidectomy hypocalcemia among patients who received vitamin D preoperatively in comparison to the patients who didn't receive, provided that whole included patients have preoperative normal both serum calcium and vitamin D levels. Subjects and methods: 100 patients who had complete thyroidectomy at Assiut University Hospital's General Surgery Department between October 2019 and January 2021 for toxic, nontoxic goiters, or malignant thyroid pathology.  The individuals that were enrolled in the study varied in age from 25 to 60. Group A who received vit D before operation.  Group B who received placebo. Resultspostoperative calcium level was substantially reduced among the control group in comparison to the study group (7.10 ± 1.81 vs. 8.15 ± 0.58 (mg/dl).  In case of the study group, there was no statistically substantial variation between pre-and postoperative calcium level (8.27 ± 0.29 vs. 8.15 ± 0.58 (mg/dl) but in case of control group, there was substantial drop in serum calcium (8.23 ± 0.27 vs. 7.10 ± 1.81). Conclusion: Our work demonstrates that thyroidectomy without preoperative vitamin D supplementation might result in postoperative hypocalcemia in patients of all ages. Vitamin D supplements used before surgery may halt postoperative hypocalcemia, enabling a safe and quick release from the hospital. In the end, this will increase patient happiness and result in considerable cost savings.