Objective: To investigate the viability of utilizing preoperative serum vitamin D levels as a predictor of postoperative transient hypocalcemia in patients who were undergoing total thyroidectomy in our population. Study Design: Prospective Observational study. Setting: Shifa International Hospital Islamabad, Pakistan. Period: 1st July 2020 to 30th June 2022. Material & Methods: All the data was collected prospectively. Patients are divided into two groups depending on the pre- operative vitamin D levels. The preoperative vitamin D levels are checked on day of admission before the surgery. After the surgery, their post-operative serum calcium levels are checked at 6 hours, 24 hours and 48 hours. Intact PTH levels are also checked after the surgery and correlation of transient hypocalcemia with intact PTH levels is also checked. Results: Our results strongly predict that serum Vitamin D levels and intact parathyroid hormone (PTH) levels are diagnostic indicators of transient hypocalcemia in post thyroidectomy patients. Conclusion: Our study shows: Pre-operative vitamin D is an early indicator of hypocalcemia in post-thyroidectomy patients. Serum intact parathyroid hormone levels is an early indicator of hypocalcemia in post-thyroidectomy patients.