AIM: To evaluate the efficacy of granulocyte colony stimulating factors (G-CSF) in liver transplanted patients with hepatitis C (HCV) recurrence and Pegylated-IFN α-2b induced neutropenia, and to evaluate the impact of G-CSF administration on virological response.METHODS: Sixty-eight patients undergoing antiviral treatment for post-liver transplantation (OLT) HCV recurrence were enrolled.All patients developing neutropenia received G-CSF.RESULTS: Twenty three (34%) received G-CSF.Mean neutrophil count at the onset of neutropenia was 700/mmc (range 400-750/mmc); after 1 mo of G-CSF it increased to 1210/mmc (range 300-5590/mmc) ( P < 0.0001).Three patients did not respond to G-CSF.Treatment duration was similar in neutropenic and non-neutropenic patients.No differences in the rate of discontinuation, infections or virological response were observed between the two groups.G-CSF was protective for the onset of de novo autoimmune hepatitis ( P < 0.003).CONCLUSION: G-CSF administration is effective in the case of Peg-IFN induced neutropenia increasing neutrophil count, prolonging treatment and leading to sustained virological response (SVR) rates comparable to non-neutropenic patients.It prevents the occurrence of de novo autoimmune hepatitis.