Early postoperative infections are one of the major causes of morbidity and mortality following orthotopic liver transplantation. The severity of these infections may be increased in patients with neutropenia. There are no guidelines on the use of granulocyte colony-stimulating factor (G-CSF) for the treatment of neutropenia in posttransplant liver recipients. However, it has been recommended by several authors. We have herein presented two patients who were treated effectively with G-CSF. Both patients developed severe neutropenia (<500/mm(3)) on the third postoperative day, and received intravenous G-CSF administration for 3 days. The neutrophil counts gradually increased and additional infusions were not needed. The immunosuppressive and prophylactic treatments were not altered. G-CSF administration was used effectively for 3 days in our two patients. No evidence of infectious or acute rejection episode was encountered during or following G-CSF treatment.