Meckel's diverticulum is one of the commonest congenital anomalies of the gastrointestinal tract. Two cases requiring emergency laparotomy due to massive gastrointestinal bleeding are presented. Only at laparotomy the correct diagnosis was established. In the first case a segment of small bowel was resected and diverticulectomy was performed in the second case. Both patients are free of complaints now at 2 and 3 years of follow-up respectively. The genesis of diverticular bleeding, the difficulties of the preoperative diagnosis of the complicated diverticulum and the uncertain indication for operation in cases of uncomplicated diverticulum are discussed and the literature is reviewed.