The role of completion thyroidectomy after lobectomy for well-differentiated thyroid carcinoma remains controversial. The purpose of the present study is to compare the relative safety of a one-stage versus a two-stage approach in the management of thyroid cancer. Thirty consecutive patients with thyroid carcinoma were studied. In 14 patients, frozen-section diagnosis of carcinoma allowed total thyroidectomy at the initial operation. In 16 patients, carcinoma was found only on permanent section; thus, completion thyroidectomy was undertaken as a second stage. Transient hypocalcemia occurred in one patient in each group (one-stage, 7%; two-stage, 6%). There was one unilateral recurrent nerve paresis in the one-stage group and none in the two-stage group. We conclude that a two-stage procedure is a safe and effective approach for the treatment of thyroid cancer and can be employed in those instances in which the diagnosis of malignancy is insecure at the initial operation.