Gastric leiomyomas are benign smooth muscle tumors that predominantly affect geriatric canines. The clinical significance of these tumors varies. Often they are incidental findings on necropsy, however, obstruction of the gastric lumen can occur. Complete surgical resection is the treatment of choice, though it is not without consequence. Most tumors occur at the cardia or gastroesophageal junction and removal can involve vagotomy, gastroesophageal sphincter removal or severe decrease in gastric lumen size. Physiologic consequences of subtotal gastrectomies include an increased incidence of cholelithiasis, altered gastrointestinal motility, regurgitation and dumping syndrome. The aim of this paper is to provide a concise overview to the clinical signs, diagnosis, treatment and post-operative management of a dog with a large gastric leiomyoma.