Ovarian hyperstimulation syndrome (OHSS) is the most serious complication of ovulation induction with exogenous gonadotropins, such as human menopausal gonadotropin and follicle‐stimulating hormone. These hormones are considered to increase capillary permeability and cause third space fluid shift. We report an autopsy case of severe OHSS in a 28‐year‐old Japanese female. The patient developed bilateral chest pain and progressive dyspnea during the course of administration of human gonadotropins. Pleural effusion and hypouresis clinically disappeared 4 days after the onset of the symptoms, but the patient died suddenly of rapid respiratory insufficiency. Autopsy examination revealed massive pulmonary edema, intra‐alveolar hemorrhage and pleural effusion without any evidence of pulmonary thromboembolism. Histopathological examination of the ovary demonstrated multiple well‐developed follicle formations, consistent with OHSS. It is very important to recognize that massive pulmonary edema can occur in a patient with OHSS. To the best of our knowledge, this is the first autopsy report of a patient with severe OHSS.