Summary. Hepatitis C virus (HCV) treatment requires maximal adherence to pegylated interferon (Peg-IFN) and ribavirin to achieve a sustained virologic response (SVR). Neutropenia is the most common cause for Peg-IFN dose reduction. Our objectives were to evaluate the effectiveness, safety and cost-effectiveness of granulocyte colony-stimulating factor (G-CSF) versus Peg-IFN dose reduction for HCV therapy-associated neutropenia in treatment naïve adults. We conducted a systematic review to identify controlled trials and observational studies. Study selection, quality assessment and data extraction were completed independently by two investigators. Cost-effectiveness and cost-utility analyses compared G-CSF with dose reduction. Nineteen studies were included. In one trial, the SVR for those receiving G-CSF was 54.5% (95% CI: 34.7–73.1) compared with 26.3% (95% CI: 11.8–48.8) for dose reduction. The remaining studies were case series or retrospective cohorts and provided weak evidence for the relationship between SVR and G-CSF. The risk of adverse events, including infection, associated with G-CSF was low (13.1%; 95% CI: 8.0–20.8) and clinically insignificant. G-CSF had an incremental cost-effectiveness ratio of $41 701 per SVR achieved in genotype 1, and $16 115 per SVR achieved in genotype 2 or 3. Estimates were robust under a variety of resource and intervention scenarios. While administration of G-CSF may enable patients to remain on or resume optimal HCV therapy, there was weak evidence that this improves the likelihood of SVR compared with dose reduction. Adverse effects of G-CSF are mild. The economic evaluation was inconclusive.