The age influence on the prognosis of papillary thyroid carcinoma was analyzed in a group of 67 patients. A marked decline in cause-specific survival was found for patients older than 60 years of age at the time of diagnosis. In order to find a tumor-biological explanation of the prognostic difference between patients below and above 60 years of age, several clinicopathological and histomorphological features were analyzed. Tumors from patients older than 60 years of age showed significantly more mitotic activity and nuclear polymorphism, fewer psammoma bodies, and more frequent extrathyroidal invasion and distant metastases. The results indicate that 60 years of age the time of diagnosis may be the "prognostic break-point" for papillary thyroid carcinoma.