During July 1991, tissue specimens were sent to the authors from a necropsy of a captive Orcinas orca named Prince. The whale had been captured in Iceland, then held in Japan before shipment to Ocean Park Corporation in Hong Kong. The tissue samples for parasitological examination included pancreas, duodenal ampulla, and posterior/anterior mesenteric lymph nodes. Tissue sent for histopathological examination included spleen, liver, lymph nodes, lungs, kidney, adrenals, aorta, myocardium, esophagus, stomachs, duodenum ampulla, duodenum, ileum, and pancreatic duct. In the inner smooth muscle layer of the muscular tunic of the third stomach there was a well encapsulated abscess filled with large numbers of parasite ova. The abscess had a center containing large numbers of neutrophils further surrounded by a thick fibrous connective tissue capsule. Small multifocal infiltrates of lymphocytes surrounded the abscess. An encapsulated abscess filled with parasite ova was also found in the duodenum ampulla and the anterior mesenteric lymph node. However, only the duodenal ampulla tissue were found infected with adult trematodes identified as Pholeter gastrohilus (Kassack, 1910) Odhner, 1914. Flukes were found in cysts, usually in pairs, under the mucosa of the duodenal ampulla. Eggs found in section of all infected tissue were identical to those of P. gastrophilus. These worms are usually found in small odontocetes. This is the first report of this parasite from 0. orca and the first report of problems caused by this worm to lymph tissue. To establish just what role these parasites may play in the general health of other odontocetes, both wild and captive, future examinations should include looking for these small, encysted trematodes.