Extramural duodenal diverticulum along the convex margin of the duodenum is a rare entity. Though its exact etiology is not clear, diverticulum of duodenum usually occurs at weak spots in duodenal walls near the major and minor duodenal papillae. Here we present a case, where we found an unusual diverticulum at the junction of the second and third parts of the duodenum. This was unique as it was very prominent with about 3 cm diameter and was along the lateral convex margin. Gastroenterologist and surgeons who deal with gastrointestinal obstructions or infections should be alert about this particular variation.