The origin of psammoma bodies in cul-de-sac fluid must always be explained. Multiple, histologically benign, predominantly peritoneal foci of tubal-like epithelium are described in a woman with endometriosis and psammoma bodies in the cul-de-sac fluid. Because no primary ovarian neoplasm was present, the diagnosis of endosalpingiosis was made. The pathogenesis and significance of endosalpingiosis are discussed.