Hypocalcemia is defined by a serum calcium level less than 80mg / l “2 mmol / l.”This is one of the common and the most worrying complications of total thyroidectomy.Hypocalcemia in our study subject is related to hypoparathyroidism which is most often transient and asymptomatic, and secondary to a trauma or a devascularization of the parathyroid glands at the time of surgery.We may in some cases be confronted to a definitive hypoparathyroidism which is rare and always secondary to irreversible damage of the parathyroid, requiring replacement therapy for life, and can therefore expose the patient to dreadful complications, forcing the healthcare team to submit him to regular monitoring.Our work is a retrospective study of 172 patients treated at the ENT department of the Military Hospital Moulay Ismail in Meknes during the period extending from January 2008 to December 2010. The aim of this work is to study the epidemiological, clinical and biological features of our patients who developed this post-total thyroidectomy hypocalcemia, and the relationship of this hypoparathyroidism with the thyroid disease treated and the type of surgery used and comper the results of this study with the literature’s data. The hypocalcemic patients in our series were adults aged 52 years on average more often women than men with hypocalcemia, it was revealed by the systematic determination of serum calcium the first and the second day of the post- total thyroidectomy.Of a total of 85 cases of hypocalcemia, only the 12 symptomatic patients were started on vitamin D and calcium supplementation. The treatment used is based on analogues of vitamin D and calcium. It allowed the healing of our 6 symptomatic patients meaning (50% of symptomatic patients). 90.6% of hypocalcemic patients recovered normal parathyroid function after one year of regular monitoring.Prevention is the best way to reduce the incidence of post-total thyroidectomy hypocalcemia and to avoid the definitive hypoparathyroidism. It consists of a caution from any surgeon during the surgical procedure, allowing the preservation of the parathyroid glands and vascularization