CASE DESCRIPTION A 7-year-old 44-kg (97-lb) neutered male Great Pyrenees was referred for evaluation because of episodic dyspnea with cyanosis of 1 to 2 weeks' duration. Three days prior to evaluation, the clinical signs had worsened, including 1 episode of collapse. CLINICAL FINDINGS Thoracic radiography and CT revealed a well-delineated soft tissue mass, located approximately 1.5 cm cranial to the carina and occupying almost 90% of the tracheal lumen. A CBC and serum biochemical analysis were performed, and all results were within reference limits. TREATMENT AND OUTCOME Tracheoscopy confirmed the presence of a broad-based bilobate mass that was protruding from the right dorsal aspect of the trachea and occupied almost the entire tracheal lumen. The mass was successfully resected by endoscopic-guided electrocautery ablation. Findings of histologic evaluation were consistent with a diagnosis of liposarcoma. Immediately following the ablation procedure, the previously noted clinical signs of respiratory tract disease resolved. On follow-up examination 12 months later, no regrowth of the mass was evident on thoracic helical CT and tracheoscopy. CLINICAL RELEVANCE Endoscopic-guided electrocautery ablation of tracheal liposarcoma was a safe and effective minimally invasive treatment for the dog of this report. The procedure was brief and appeared to be well tolerated, resulting in immediate improvement of clinical signs.