Introduction : The objective of this study was to analyze the complication rates after completion thyroidectomy and compare them with primary total benign and malign thyroidectomy causes in total of 647 patients. Patients and Methods: Among 647 patients, there were 159 receiving completion thyroidectomy for differentiated thyroiud cancer (DTC) (Group 1); 217 patients receiving total thyroidectomy for DTC (Group 2) and 271 given total thyroidectomy for benign diseases (Group 3). Results: When groups were compared for complications, there were no significant difference except temporary hypocalcemia between completion thyroidectomy and total thyroidectomy for DTC. When the total thyroidectomies were compared (Group 2 and 3), there were no significant difference observed except unilateral temporary RLN palsy. Conclusion: With improvements in surgical technique and experience, complication rates of thyroidectomy performed for benign or malign diseases are reduced. In spite of the improvement in surgical experience, temporary RLN palsy and hypoparathyroidism are the main complications in completion thyroidectomies which need special attention. To evaluate the patients more carefully in preoperative period and performing adequate thyroidectomy appears more logical.