Human granulocyte colony-stimulating factor (G-CSF) is a hematopoietic hormone promoting the growth, proliferation, differentiation and maturation of myeloid and leukocytic lineages. G-csfs have been used to improve granulocyte count in neutropenic patients, reduce the incidence and duration of neutropenia in patients receiving cytotoxic chemotherapy and to mobilize peripheral blood stem cells prior to leukapheresis for using in both autologous and allogeneic hematopoietic cell transplantation. In general, side-effects are mild to moderate and life threatening side-effects like splenic rupture are very rare. We herein, report a case of spontaneous splenic rupture secondary to high-dose G-CSF use (20 mcg/kg/day), in a healthy female allogeneic donor of peripheral-blood stem cell (PBSC) .