Laryngotracheal invasion by well-differentiated thyroid carcinoma is an uncommon occurrence. Recommendations for therapy have primarily included total laryngectomy or shaving of the tumor from laryngeal or tracheal cartilages. Clear guidelines have not been established for the applicability of partial laryngeal resections. In a retrospective analysis of patients with thyroid carcinoma, 13 patients had airway invasion. Of the five patients with laryngeal involvement, three were treated by a partial laryngeal resection. An experimental study was undertaken to determine more precisely the amount of cricoid cartilage which could be resected without reconstruction. Varying amounts of cricoid cartilage were resected. The results indicate that 25% of the cricoid cartilage may be resected without appreciable airway narrowing. On the basis of the retrospective analysis and experimental study, we feel a partial laryngeal resection is possible in most cases of airway invasion by thyroid carcinoma.