We describe a 24-year-old pregnant woman complicated by cyclic neutropenia (CN), who was successfully treated with granulocyte-colony stimulating factor (G-CSF). Her white blood cell (WBC) and neutrophil count fluctuated from 2,600 to 4,600/microl, and 26 to 2,530/microl, respectively. The peak neutrophil count gradually decreased as pregnancy advanced, resulting in the disappearance of its cyclicity. At 39 weeks of pregnancy when the neutrophil count became 84/microl, the patient was started on G-CSF and her neutrophil count increased to 1,550/microl on the fourth day after delivery. She delivered a healthy baby without any complications at 39 weeks of pregnancy.