An ectopic pregnancy in the abdominal organs is very rare. Primary intestinal pregnancy is considered the rarest form of extrauterine pregnancy, and only a few well-documented cases have been reported. Herein, a case of an abdominal pregnancy in a 25-year-old woman, with massive lower gastrointestinal bleeding, is reported. The source of bleeding could not be identified, despite gastroscopy, ultrasonography and angiography investigations. A diagnostic laparotomy disclosed an abdominal pregnancy, causing an erosion of the jejunal wall at the site of the pregnancy, with massive lower gastrointestinal bleeding. An abdominal pregnancy is seldom included in the differential diagnosis of lower gastrointestinal bleeding. The possibility of intestinal erosion in an abdominal pregnancy should be borne in mind in cases of lower gastrointestinal bleeding.