Objectives: The objective of the present study was to demonstrate the efficacy of the clinical application of in situ tissue engineering using a scaffolding technique for laryngeal and trachea! tissue.Methods: We have developed a tissue scaffold made from a Marlex mesh tube covered by collagen sponge. Based on successful animal experimental studies, in situ tissue engineering with a scaffold implant was applied to repair the laryiix and trachea in 4 patients.Results: In I patient with subglottic stenosis, the thyroid cartilage, cricoid cartilage, and cervical trachea with scarring and granulation were resected and reconstructed by use ofthe scaffold. In 3 patients with thyroid cancer. Ihe trachea and cricoid cartilage with tumor invasion were resected and the scaffold was implanted into the defect. Postoperative endoscopy during the observation period of 8 to 34 months showed a well-epithelialized airway lumen without any obstruction.Conclusions: Our current technique of in situ tissue engineering using a scaffold shows great potential for use in the regeneration of airway defects