Abnormal vaginal bleeding in adolescent and young women is not a rare event and can be attributed mainly to anovulatory cycles, pregnancy-related bleeding, and endocrinological disorders in this age group. Cervical polyps commonly occur during the reproductive years, especially after the age of 40. Here we present a rare reason for vaginal bleeding and dysmenorrhea in a 20-year-old woman caused by endometriosis in a cervical polyp. Twenty-year-old patient admitted to Ege University Faculty of Medicine Gynecologic clinic due to vaginal bleeding and prolapsed lesion which was seen from introitus of the vagina. She had mental retardation and seizures since infancy. Her first menstrual bleeding occurred at the age of 14 and she had regular menstrual cycles. Gynecologic speculoscopy and bimanual examination could not be performed because the patient was sexually inactive and she did not accept the bimanual vaginal examination. Magnetic resonance imaging was performed. Multiple cervical polyps and genitourinary system malformation were reported. Vaginoscopy with hysteroscope was performed and cervical polyp in 5 cm length was detected. Polypectomy was performed with operative hysteroscope without complication. No damage was occurred to hymen. Pathologic result was determined endometriosis in cervical polyp. Cervical polyp in young women is rare and endometriosis in cervical polyp is detected only in a few cases in literature. It is a reason of abnormal vaginal bleeding and dysmenorrhea. Vaginal masses that prolapse from the cervix should be examined precisely. Malignancies of the cervix, vagina and uterus should be kept in mind in patients with malformations and anomalies. We aimed to present this rare case and to show the feasibility of vaginoscopy with operative hysteroscope in sexually inactive patients. Pre-operative evaluations should be patient specific and care should be taken to avoid complications.