Enormous number of Hematopoietic growth factors like CSF, GCSF, and GMCSF have been cloned, purified and produced in E.coli. Recombinant human GCSF is a Hematopoietic growth factor, extensively used in Cancer therapy to treat Neutropenia and to combat infections, immune suppression, anti-inflammatory responses, immunomodulation, stem cell transplantation, myocardial infarctions etc. This review discusses about G-CSF signaling, mechanisms of G-CSF-induced stem cell mobilization, and influence of G-CSF on T-cell function and dendritic cell activation. An attempt has been made to link the current issues about the biology of G-CSF with its clinical uses, both present and future. It also depicts various applications of GCSF in Chemotherapy, radiation therapy and the use of GCSF in repair, regeneration of neuronal tissues etc. by Stem cells and progenitor cells.