Endosalpingiosis in female peritoneal washings can be a source of false-positive diagnoses, especially in patients with known ovarian carcinoma. In this article we report the features of endosalpingiosis in the peritoneal washings of four patients, three of whom were initially reported as "suspicious for malignancy." Two of the patients had ovarian serous tumor of borderline malignancy; however, the tumors were confined to the ovaries with no evidence of disseminated peritoneal malignancy. All four patients had histologic evidence of pelvic endosalpingiosis. It is important to recognize this entity cytologically to avoid a misdiagnosis of recurrent or disseminated malignancy.