Xanthogranulomatous endometritis is a rare pathologic finding with only five cases reported in the literature. On review of our files over the past 12 years, we found six cases of xanthogranulomatous endometritis, all associated with endometrial adenocarcinoma that had been irradiated by external beam and/or intracavitary implants prior to surgery. Histologically, these cases were characterized by foamy histiocytes with variable amounts of associated multinucleated giant cells, other chronic inflammatory cells, necrosis, calcium, cholesterol clefts, and hemosiderin. Xanthogranulomatous features were not present in the pretreatment endometrial biopsy specimens from any of the six patients. Contributory factors to the development of xanthogranulomatous endometritis such as necrosis, hemorrhage, obstruction, tumor bulk, or delay in treatment were identified. The mechanism of development of xanthogranulomatous endometritis may involve a complex interaction of elements common to the development of xanthogranulomatous change in other organs (obstruction, inflammation, and a lipid source) as well as elements unique to irradiated tissue (generation of free radicals and lipid peroxidation). These cases indicate that radiation injury in the setting of endometrial adenocarcinoma is an additional etiopathologic finding ofulomatous endometritis.