An 11 year old thoroughbred mare was presented in veterinary Clinical Complex of College of Veterinary and Animal Science, Bikaner with a history of abdominal pain. The mare was examined clinical and the condition is diagnosed as colic. The animal was kicking and rolling over the ground due to severe pain and treatment for colic was initiated immediately. Soon after, she was fall down and her respiratory rate increased suddenly and started trembling. She became recumbent and died within 10 minutes. A 22 cm long rent and rupture of the diaphragm was found in post mortem examination. The lungs were completely collapsed and there was severe hemothorax. The cause of death was determined to be hemorrhagic shock and asphyxia due to lungs collapse.