Roentgenographic features of the small bowel were characteristic in 16 of 17 patients with the Zollinger-Ellison syndrome.The features include megaduodenum, small bowel edema, increased intraluminal fluid and, frequently, dilatation of the jejunum. On occasion, the ileum is also dilated. Abnormalities of the colon were noted in 2 patients.Because of these changes, the responsibility of recognizing the Zollinger-Ellison syndrome devolves upon the radiologist in most instances.Although complete gastric secretory studies are a valuable adjunct, they should be considered supportive data and not be relied upon as definitive studies.By applying these criteria, false negative diagnoses should be few. False positive diagnoses, however, are inevitable.