We report a 37-year-old pregnant woman with paroxysmal nocturnal hemoglobinuria (PNH) treated with eculizumab. She had been diagnosed with PNH-aplastic anemia at age 19 years, and started to receive eculizumab at age 35 years. Thereafter, she had no hemolytic attacks. She became pregnant 2 years later, and treatment with eculizumab was continued. During her pregnancy, she showed no exacerbation of hemolysis. She delivered a girl by Caesarean section at 37 weeks and 3 days of gestation. Postpartum, anticoagulant therapy was started. Although mild hemolysis and a rise in FDP/Ddimer were seen, she had no symptoms of thrombosis. Ten days after delivery, she and her baby were discharged. Eculizumab was present in the first breast milk and cord blood but was below detectable levels. The cord blood showed blockage of hemolysis.