A 19-year-old Warmblood mare presented to the Cornell University Equine and Food Animal Hospital for chronic colic. She had a 9-month history of repeated colic, with episodes increasing in frequency and severity. She had a severe colic at a show 2 weeks prior which resulted in the mare being off-feed. On presentation the mare was quiet, alert, and responsive. Temperature, pulse, and respiration rate were within normal parameters. Physical examination revealed a prolonged skin tent, icteric sclera, and a prolonged CRT. A complete blood cell count, chemistry panel, rectal examination, and gastroscopy were within normal limits. Ultrasound of the abdomen revealed dilated loops of small intestine surrounding the spleen. Over the course of the next two weeks, the horse had intermittent colic and required decompression (reflux) and repeated gastric lavage.. Ultrasound of the abdomen during these episodes revealed a severely distended stomach and duodenum. These findings were suggestive of a gastric impaction or delayed gastric emptying. Exploratory laparotomy was performed to determine the underlying etiology and revealed a thickened pylorus and proximal duodenum. However, a good examination of the affected area was not possible due to the lack of surgical exposure. The horse recovered uneventfully from surgery and continued to colic due to a gastric-emptying defect. Due to the poor prognosis and the horse’s overall quality of life, the owners elected euthanasia and a necropsy performed.