Gastroduodenal intussusception is a rarely documented condition which occurs usually when a mobile leading gastric tumor prolapses into the duodenum with subsequent invagination of a portion of the stomach wall. An example of this condition, associated with a gastric leiomyoma, is presented herein. The patients clinical manifestations were non-specific. Correct preoperative diagnosis was made by upper gastrointestinal series and computed tomography (CT) study. The typical radiographic signs include distal converging gastric folds, infoldings and outpouchings of the gastric wall, gastric intussusceptum presenting as a filling defect and a leading tumor in the dilated duodenum. The histological nature of the leading tumor can not be determined until examination of the resected specimen.