Endometrial polyp is the lesion frequently found by hysteroscopy. The presence of endometrial polyp is associated with abnormal uterine bleeding and is probably associated with infertility. Until today, clinical guidelines for endometrial polyp remain elusive. The aim of this preliminary study was to estimate whether the shape of endometrial polyps affects the response to the treatment with an oral contraceptive (OC). We performed a retrospective case series study on 50 women diagnosed as endometrial polyps by hysteroscopy and managed by the administration of OC. Hysteroscopy was performed in the follicular phase of the menstrual cycle before medical treatment. Endometrial polyps were classified as pedunculated polyps (n = 25) or sessile polyps (n = 25). After diagnosis, OC was administered for 2-5 months (median 3 months) intermittently: To quantify the regression rate of lesions, the area index of endometrial polyps was assessed. In the study group, when comparing the efficacy of treatment with OC, there was a statistically significant difference in the regression rate between sessile polyps and pedunculated polyps (76% vs. 44%, p = 0.042). We conclude that sessile polyps are more sensitive to OC treatment than pedunculated polyps, implying usefulness of the hysteroscopic classification of the shape of polyps in the management of endometrial polyps.