Omenta removed either at surgery or autopsy were examined for benign glandular inclusions. Multiple random sections failed to reveal these inclusions in any of the 37 male or 27 female autopsy specimens. None of the 22 male surgical specimens contained benign cysts, whereas these inclusions were found in 19 of 128 (14.8%) of the female surgical specimens. One female patient had endometriotic cysts, two had mesothelial cysts, and 13 had inclusions histologically similar to oviduct epithelium (endosalpingiosis). Another female had both endometriotic cysts and endosalpingiosis, whereas two had both mesothelial cysts and endosalpingiosis. All 16 patients with endosalpingiosis had inflammatory tubal disease (e.g., chronic salpingitis, hydrosalpinx, tubal pregnancy). Four of these 16 females also had an ovarian tumor. These ovarian tumors included one serous cystadenoma, two serous cystadenomas of borderline malignancy, and one serous cystadenocarcinoma. We conclude that the endosalpingiotic inclusions are benign and occur exclusively in females. Since they are found in association with ovarian tumors, it is important to exclude well-differentiated metastases. Our findings support a close relationship between inflammatory tubal disease and endosalpingiosis.