We report a case of duodenal diverticulitis and describe the helical computed tomography and contrast-enhanced magnetic resonance imaging (MRI) study findings. Due to its uncommon appearance, this lesion is not typically included in the differential diagnosis of pancreatitis or cholecystitis. The imaging findings of duodenal diverticulitis can be very suggestive of its diagnosis or can narrow the differential diagnosis. To our knowledge and in spite of the wide use of MRI, the contrast-enhanced MRI features of this entity, as described below, have not yet been reported in the literature.