Objective: To investigate the effect of recurrent laryngeal nerve (RLN) identification on the complications after total thyroidectomy and lobectomy. Methods: Total 134 consecutive patients undergoing total thyroidectomy or thyroid lobectomy from January 2003 to November 2004 were investigated retrospectively. Patients were divided into two groups: RLN identified (Group A) or not (Group B). The two groups were compared for RLN injury and hypocalcaemia. Results: The numbers of patients and nerves at risk were 71 and 129 in Group A, and 63 and 121 in Group B, respectively. RLN injury in Group A (0) was significantly lower than that in Group B (5[7.9%]) patients, 7 [5.8%] nerves) for the numbers of patients (P=-0.016) and nerves at risk (P=0.006). Temporary hypocalcaemia was significantly higher in Group A than in Group B (14 [24.1%] vs 6 [10.3%], P=0.049).Permanent complications in Group B were significantly higher than those in Group A (13 [20.6%] vs 4 [5.6%], P=0.009). Conclusion: RLN injury was prevented and permanent complications were decreased by identifying the whole course and branches of the recurrent laryngeal nerve during total thyroidectomy.