A 5 years old gelding (Thoroughbred, Equus caballus) had shown severe abdominal pain, colic, after overeating of hay in the feed storage. following through treatment, it subsequently died. Grossly, the large colon was impacted with firm mass of food and congestion of blood vessel in the intestinal wall. There were mild peritonitis and pleuropneumonia. This case demonstrates typical large colon impaction with hard consistence ingesta due to improper management of horse.