An abnormality arising in the small intestine may be focal, long-segment, or diffuse. The abnormality may alter the contour of the intestine; it can protrude into the lumen or extend outside of the expected luminal contour. A disorder involving the mucosa or submucosa disrupts the normal fold pattern of the small intestine. By analyzing the morphology of a focal lesion or the distribution, location, and morphology of the intestinal folds, the radiologist can come to a specific diagnosis or construct a graded differential diagnosis [1]. This article presents a simplified approach to the differential diagnosis of small intestinal diseases by combining this roentgen analysis with the clinical history.