Background: Postoperative hypocalcaemia, secondary to hypoparathyroidism, is the most common complication observed in patients who undergo bilateral thyroid resection. Although hypocalcaemia is self-limiting in most patients and does not require treatment, symptomatic hypocalcemia is of concern. The aim of this research was to identify PTH-24h post-operatively as a simple predictor of early postoperative hypocalcemia following total thyroidectomy for simple multi-nodular goiter.Methods: Fifty patients undergoing total thyroidectomy for simple multi-nodular goiter were included in a prospective controlled study with follow up of 48 hours postoperatively for the development of hypocalcemia both clinically and biochemically correlating it to the level of serum iPTH thus allocating patients in two groups; those who developed hypocalcemia (whether clinically or biochemically) and those who didn`t.Results: A highly significant difference between PTH percent of decline was noted for the patients who developed biochemical hypocalcaemia and those who did not. Conclusion:Serum PTH 24-h after total thyroidectomy is a reliable early predictor of hypocalcemia.