Operations for well-differentiated thyroid carcinoma should be individualized on the basis of the pathologic variety and clinically demonstrated extent of carcinoma. Although precise studies have not been carried out specifically to provide treatment plans for various clinical situations, experience does provide management policies to follow currently. The basic operation is thyroid lobectomy. This appears adequate for minimal carcinoma, small (under 1.5 cm diameter) carcinoma, and low grade encapsulated follicular carcinomas of the thyroid. Extent of operation for other clinical patterns of well-differentiated thyroid carcinoma is individualized to permit control of the disease in the neck. If well-differentiated carcinoma is recognized only postoperatively, a decision for reoperation can relate to evidence of multicentricity. Improvements in autotransplantation of parathyroid tissue and diagnostic needle biopsy have permitted improvements in therapy in recent years.