Cyclooxygenase-2 (COX-II) is an inducible enzyme that is responsible for the production of prostaglandin E2 (PGE2), which is often upregulated in neoplastic conditions. Expression of COX-II is documented in the majority of human pancreatic adenocarcinomas and in many epithelial neoplasms in humans and animals. The purpose of this study was to assess a series of feline pancreatic adenocarcinomas for the expression of COX-II. Eight feline pancreatic adenocarcinomas (5 poorly differentiated ductular variants and 3 well-differentiated acinar variants) were included. Immunohistochemical staining showed that COX-II was expressed in 2 (both poorly differentiated ductular variants) of the 8 neoplasms (25%). Approximately 10% of the epithelial cells from these 2 neoplasms expressed intense cytoplasmic staining. However, because feline pancreatic adenocarcinoma does not appear to consistently express COX-II, it is not a useful prognostic indicator for this group of feline neoplasms. In addition, COX-II inhibitors are not likely to be effective therapeutics for cats with this neoplasm.