Abstract Endometriosis is defined as the presence of ectopic foci of endometrial tissue outside the uterine cavity. Many patients are asymptomatic, but others present protean symptoms, including headache, cyclic hemoptysis, pleural effusion, and ascites depending on the endometrial implantation sites. Although massive ascites has been reported as a manifestation of endometriosis, hypovolemic shock is unusual. We report a case of endometriosis presenting as shock and bloody ascites to show that endometriosis can result in acute abdomen with shock. A 29-year-old female presented to our Emergency Department (ED) complaining of light-headedness and palpitations. Examination suggested hypovolemic shock. Ultrasonography revealed massive ascites and paracentesis showed bloody ascites. Exploratory laparoscopy showed endometriosis over the left broad ligament. After fluid resuscitation and electrocauterization of the endometriosis, the patient's condition stabilized, and she was discharged 5 days after admission. This case is presented to raise awareness that endometriosis can present with hypovolemic shock.