Previously, dogs with canine parvovirus-induced neutropenia have not responded to treatment with recombinant human granulocyte-colony stimulating factor (rhG-CSF). However, recombinant canine G-CSF (rcG-CSF) has not been previously evaluated for treatment of parvovirus-induced neutropenia in dogs. We assessed the effectiveness of rcG-CSF in dogs with parvovirus-induced neutropenia with a prospective, open-label, nonrandomized clinical trial. Endpoints of our study were time to recovery of WBC and neutrophil counts, and duration of hospitalization. 28 dogs with parvovirus and neutropenia were treated with rcG-CSF and outcomes were compared to those of 34 dogs with parvovirus and neutropenia not treated with rcG-CSF. We found that mean WBC and neutrophil counts were significantly higher (P < 0.05) in the 28 dogs treated with rcG-CSF compared to disease-matched dogs not treated with rcG-CSF. In addition, the mean duration of hospitalization was reduced (P = 0.01) in rcG-CSF treated dogs compared to untreated dogs. However, survival times were decreased in dogs treated with rcG-CSF compared to untreated dogs. These results suggest that treatment with rcG-CSF was effective in stimulating neutrophil recovery and shortening the duration of hospitalization in dogs with parvovirus infection, but indicate the need for additional studies to evaluate overall safety of the treatment.