PURPOSE: The use of thyroidectomy has increased as a diagnostic technique for thyroid disease. However, performance of a, thyroidectomy is accompanied with complications. Post-thyroidectomy complications include recurrent laryngeal nerve palsy, hypocalcemia, hematoma, infection, and thyroid storm. The aim of this study was to determine the clinical incidence and to evaluate complications after a thyroidectomy, including recurrent laryngeal nerve palsy, hypocalcemia, hematoma, and scaring, following a retrospective review of cases. METHODS: From July 2004 to May 2006, 661 consecutive patients that had undergone a thyroidectomy were identified. Through a retrospective review, we evaluated the incidence and type of complications, including recurrent laryngeal nerve palsy, hypocalcemia, hematoma, and postoperative scaring. RESULTS: 1) Recurrent laryngeal nerve palsy was a very serious complication, but had a very low incidence. Eight cases out of 661 cases developed and most of the cases developed after a total thyroidectomy. 2) Hypocalcemia was the most common complication. Each incidence of hypocalcemia of methods of thyroid surgery was significant (P= 0.019) but, thyroid disease did not have significant difference (P=0.071). 3) The incidence of postoperative hematoma was 2.74% (18/655). Graves’ disease was more predominant than other diseases. CONCLUSION: Post-thyroidectomy complications and cosmetic problems include recurrent laryngeal nerve palsy, hypocalcemia, hematoma, and postoperative scar. An understanding of the incidence and review of complications after a thyroidectomy may reduce their incidence.