Exercising upper airway endoscopic evaluation was performed in 7 horses with a history of poor performance after partial arytenoidectomy. Treadmill endoscopy revealed axial deviation of the ipsilateral aryepiglottic fold in all horses. Dynamic collapse of one or more additional upper airway structures was also observed. In 4 horses, laser resection of soft tissue structures that obstructed the upper airway was performed. After laser surgery, 3 horses raced and one performed adequately as a riding horse. Of the remaining 3 horses, 2 raced at a lower class and one performed adequately as a riding horse. In this population of horses, dynamic endoscopy of the upper airway was critical for case management. Based on our observations, horses post arytenoidectomy can have dynamic collapse of the ipsilateral aryepiglottic fold and laser resection of the fold may help resolve the performance problem.