Data from 576 patients with papillary thyroid cancer were retrospectively analyzed. With a median follow-up of 10 years and three months, there were six deaths from, and 84 recurrences of, thyroid cancer. Of the latter, 16 (19 percent) could not be eradicated. Death from thyroid cancer occurred only in those 30 years of age or over at the time of diagnosis and only in patients with primary tumors larger than 1.5 cm in diameter. Locally invasive tumor was associated with a poor prognosis. Cervical lymph node metastases found at initial surgery were associated with higher recurrence rates but not higher mortality rates. Treatment with total thyroidectomy, postoperative radioiodine and thyroid hormone resulted in the lowest recurrence and mortality rates except in those patients with small primary tumors (less than 1.5 cm diameter) in whom less than total thyroidectomy and postoperative therapy with thyroid hormone alone gave results which did not differ statistically from those achieved with more aggressive therapy. No important differences in outcome were observed when cervical lymph node metastases were simply excised or more aggressively treated by neck dissection. External radiation and as initial adjunctive therapy adversely influenced outcome.