We report a case of heart failure and pulmonary edema in patient with Graves disease during recovery from general anesthesia for cesarean section. A 34-year-old multigrivida, at 35 weeks gestation underwent emergency cesarian section for preterm labor, twin pregnancy and polyhydramnios. She has been treated with Graves' disease for 5 years. After premedication with propranolol and glycopyrrolate, anesthesia was induced with thiopenthal and maintained with O2 -N2 O-enflurane. At the end of skin closure, heart failure and pulmonary edema were developed. On auscultation, systolic murmur was audible at the left sternal border and immediate echocardiography revealed mitral valve prolapse accompanied with mitral regurgitation. After proper treatment, she was discharged without complication at 14 days after surgery.