In 98 follicular thyroid carcinoma patients with a follow-up of 10-32 years, 10-year survival varied in subgroups from 15.5-63.4%. Survival with encapsulated primary tumors was 46.7%, compared to 26.9% in widely invasive tumors, and varied from 59.9-35.8% with growth pattern. In patients younger than 60 years of age at diagnosis 10-year survival was 68% of expected survival, compared to 32% in patients older than 60. Patients treated after 1970 had an improved survival of 24.2%. Thirty-one patients had previous thyroid operations for benign lesions. Review of histopathologic slides and medical records demonstrated follicular adenomas in 17 cases, and overlooked carcinomas in 11. Calculating survival from the first surgical intervention improved reported 10-year survival by 14.5%. Papillary carcinoma patients matched for age and sex had significantly better 10-year survival. © 1992 Wiley-Liss, Inc.