BACKGROUND: The surgical management of papillary thyroid cancer is not only controversial with regard to the surgery of the thyroid gland itself but also with regard to the management of regional lymph nodes. The presence of regional lymph node metastasis is not related to the prognosis, but affects the local recurrence rate, and a reoperation in the central neck is technically more difficult than a primary procedure. The central neck lymph node dissection is mandatory during the primary operation in order to reduce lymph node recurrence in the central neck and to avoid reoperation, but there is question about the necessity of lymph node dissection contralateral to the primary tumor when it is confined to one lobe only. METHODS: Thus, we analyzed the central neck lymph node metastasis of 80 patients with papillary thyroid cancer who underwent a total thyroidectomy and central neck dissection. RESULTS: For the 53 patients with the primary tumor confined to one lobe and with a clear opposite lobe, the rate of contralateral paratracheal lymph node metastasis was 26%, and for the 19 patients with a microcarcinoma in opposite lobe, the rate of contralateral paratracheal lymph node metastasis was 63%. However, it was difficult to identify the microcarcinoma in the opposite lobe based on the gross finding during the operation. As a result, the overall probability of contralateral lymph node metastasis was 36% when the primary tumor was grossly confined to on lobe. The mass size did not correlated with the rate of contralateral lymph node metastasis. CONCLUSIONS: The bilateral node dissection appears to have been appropriate in every case of advanced papillary thyroid cancer as far as the complication rates could be maintained acceptably low.