Laryngoplasty is commonly used to treat laryngeal hemiplegia in Thoroughbred racehorses. Evaluation of the success of the laryngoplasty is traditionally determined using endoscopy. Laryngeal ultrasonography and normal ultrasonographic appearance have been reported in the standing horse, but post-laryngoplasty and ventriculectomy ultrasonographic evaluation has limited literature coverage. A prospective case series of 10 Thoroughbred racehorses with left laryngeal hemiplegia was examined ultrasonographically and endoscopically prior to 3-10 days, 30-50 days, and 6-12 months after laryngoplasty and ventriculectomy. Anatomical structures and Plica vocalis movements were described and measurements and gradings analyzed by repeated means analysis of variance (P <.05). Postsurgical ultrasonographic visualization of Ventriculus laryngis entrances was possible. The distance between Plica vocalis in exhalation was significantly larger than that during inhalation (P <.05). Pre- and postsurgical caudal Basihyoideum and rostral Cartilago thyroidea depth was significantly different in some instances (P <.05). No significant differences in the Muscularis cricoarytenoideus lateralis measurements were found. Complications in the extra-luminal structures were found in seven horses including soft tissue swelling, seroma, and hematoma. A luminal Plica vocalis abscess and Plica vocalis granuloma were also detected ultrasonographically. Ultrasonography can be used to evaluate the post-laryngoplasty horse for assessing the success of the procedure, monitoring healing, and detecting complications.