Appendiceal endometriosis is a very uncommon clinical entity. We describe a 33-yr-old white female who presented with painless profuse rectal bleeding. Emergency colonoscopy revealed bleeding from the appendiceal opening. An emergency appendectomy was performed which controlled her bleeding. The histopathological examination demonstrated appendiceal endometriosis. Painless bleeding from appendiceal endometriosis is extremely rare; however, it should be considered when evaluating young women of reproductive age who present with rectal bleeding.