Endometriosis is a disease seen in women at reproductive age, characterized by extrauterine localization of endometrial tissue. Colonic endometriosis rarely causes acute mechanical intestinal obstruction (AMIO). It may also be presented with pelvic pain, dyspareunia, tenesmus, painful defecation related to the menstrual cycle. In the literature, 3-37% of the gastrointestinal location was reported and AMIO was observed in 7-23% of these cases. There are only few cases of mechanical obstruction related to sigmoid endometriosis mimicking colon malignancy. In this study, we aim to report a case of a 40-year-old patient with AMIO developed secondary to colonic endometriosis in light of the literature. The patient was discharged with full surgical recovery after the Hartmann procedure was performed, and the pathological diagnosis was reached as endometriosis. At the post-operative sixth-month colostomy, closure and bilateral oophorectomy were performed with the patient's will. The patient was discharged with surgical recovery and is still being regularly followed up. Endometriosis is a gynecological disease that may occur in all organ systems even though the most common location is the overs. Gastrointestinal located endometriosis should, therefore, be kept in mind in the etiology of AMIO in women at reproductive age and the related symptoms should be questioned in differential diagnosis.