Ritodrine hydrochloride (Yutopar (R)) is widely used for the treatment of premature uterine contraction with betasympathomimetic effect on the uterus but adverse effects associated with cardiopulmonary system are frequently reported. We experienced a case of pulmonary edema that occurred suddenly during cesarean section under epidural anesthesia. She had been treated with ritodrine for 3 days to arrest preterm labor of twin pregnancy. Intensive care including mechanical ventilation with PEEP via endotracheal intubation and diuretic therapy was attempted. At the 3rd day after operation patient was transferred to general ward without any sequale.