We report anesthetic management of a patient with severe ovarian hyperstimulation syndrome (OHSS). A 33-year-old woman presented with severe abdominal acites and effusion after ovarian stimulation with HMG followed by ovulation induction with HCG. She was suspected of having intraabdominal hemorrhage because of ectopic pregnancy. Emergency laparotomy was performed under general anesthesia. Massive ascites and intraabdominal hemorrhage were observed and patient was treated by adequate fluid infusion and blood transfusion. Patient was treated with non-invasive positive pressure ventilation (NPPV) after operation and recovered. It is essential to maintain a correct balance of fluids, through appropriate intravenous infusion of crystalloids, albumin, blood transfusion and an adequate urine output. Further it is important to prevent thromboembolic event. Knowledge of the clinical features, complications and acute management of OHSS will permit the anesthesiologist to treat these patients in an optimal fashion.