A 38-year-old woman had a 4-week history of vaginal bleeding, heat intolerance and palpitations. Levels of beta-human chorionic gonadotropin and thyroid hormones were abnormally high. After ultrasound diagnosis of a molar pregnancy, evacuation of the mole was planned with preoperative treatment involving the use of antithyroid drugs and plasmapheresis. Plasmapheresis was used to prepare for surgery in our patient who needed more rapid hormonal control. In conclusion, early diagnosis of molar pregnancy results in decreased incidence of significant complications related to hyperthyroidism.