The authors conducted a preliminary evaluation of the potential of superparamagnetic iron oxide as contrast material for delineation of the bowel. Ten patients with various pancreatic diseases and 18 patients with suspected retroperitoneal disease underwent T1- and T2-weighted MR imaging before and after contrast material was administered. Two radiologists reviewed randomized images and scored them for depiction of anatomic structures and abnormalities. In most patients, postcontrast T1-weighted images showed improved delineation of the retroperitoneal small bowel (duodenum), stomach, and pancreas. Postcontrast T2-weighted images showed improved delineation of retroperitoneal small bowel, para-aortic region, peripancreatic fat, and renal veins. There was no improvement in delineation of retroperitoneal diseases, except for lymphadenopathy, which was better seen on both T1- and T2-weighted postcontrast images. Preliminary results suggest that superparamagnetic iron oxide is a useful contrast agent for delineating some normal retroperitoneal structures, lymphadenopathy, and pancreatic disease and that it is less useful in evaluating other retroperitoneal masses.