FCR, the standard of care for frontline treatment of CLL patients, is associated with a high rate of neutropenia and infectious complications. GM-CSF reduces myelosuppression and can potentiate rituximab activity. We conducted a clinical trial combining GM-CSF with FCR for frontline treatment of 60 CLL patients. Eighty-six percent completed all 6 courses and 18% discontinued GM-CSF for toxicity; grade 3–4 neutropenia was observed in 30% of cycles, and severe infections in 16% of cases. ORR was 100%. Both median EFS and OS have not been reached. Longer EFS was associated with favorable cytogenetic. GM-CSF led to a lower frequency of infectious complications than the historical FCR group, albeit similar EFS and OS.