Endometriosis is a benign gynecologic disease that highly influences women of childbearing age. It is characterized by ectopic endometrial tissue. Primary umbilical endometriosis is a rare condition. It is a benign disease with endometrial tissue in an abnormal site in the navel. It may be accompanied with pain in the navel and a discolored bump. Among all locations with the potential for endometriosis, the navel has less than 1% incidence of primary umbilical endometriosis. In the present study, we reported a rare case of umbilical endometriosis revealed via a biopsy performed for a 49-year-old menopausal woman with the complaint of pain in the navel who underwent surgical excision and a biopsy after a scan.