Standard laryngotracheal reconstructive procedures are constrained by the availability of grafting materials and the ability to repair large defects. Reconstruction utilizing alloplasts may be ideal, but previous results have generally been poor. We present a two-stage procedure using Proplast to reconstruct large laryngotracheal defects in 6 dogs. A custom-made Proplast implant was inserted into a strap muscle pocket and buccal mucosa was placed in the adjacent peritracheal tissue. The muscle-Proplast composite graft was rotated to repair a large defect (3.25 cm by 2.25 cm). All 6 dogs survived. Endoscopic and histologic studies over 12 months showed continued stabilization and maturation of the implant. We feel that Proplast may be used as an alternative to autograft for reconstructing large laryngotracheal defects when the procedure is staged to allow maximal fibrous ingrowth and the implant is protected from infection.