We present a case of a middle-aged woman, who presented with abdominal pain less than 24 h following an uneventful colonoscopy for rectal bleeding. Initial diagnosis was thought to be colonic perforation. An urgent CT scan performed owing to dropping haemoglobin and blood pressure revealed a large perisplenic haematoma. An urgent laparotomy was performed in which the patient had a total blood loss of 2500 ml and required splenectomy. The patient recovered well postoperatively.Colonoscopy is a commonly performed procedure in which complications of perforation and bleeding are well recognised. This case represents one of the rare but serious complications that endoscopists and patients should be aware of to aid prevention and early diagnosis.