This report concerns 14 patients with Morbus Crohn and inflammatory conglomerat tumors between ileo-coecum and sigma. In the case of primary affliction of the ileo-coecum and secondary involvement of the sigma (group A), it is generally sufficient to perform an ileo-coecal resection and suture over the sigma, if a fistula is present. In case of Morbus Crohn afflicting primarily the sigma (group B) or simultaneous involvement of ileo-coecum and sigma (group C), a double resection is necessary. It was always possible to demonstrate the presence of an ileo-sigmoidal fistula by means of barium enema and mostly possible with barium meal or enteroclysis. We consider preoperative colonoscopy with graduated biopsies to be absolutely necessary to determine the exact stage of the illness. Fistulas can be more accurately demonstrated by radiogram than endoscopically.