A randomized, double-blind, multicenter study in 181 afebrile cancer patients with ANC levels < 500/microL receiving myelosuppressive chemotherapy was undertaken to compare sargramostim (yeast-derived recombinant human granulocyte-macrophage colony-stimulating factor, RhuGM-CSF) and filgrastim (bacteria-derived recombinant human granulocyte colony-stimulating factor, RhuG-CSF) in the treatment of chemotherapy-induced myelosuppression. Patients received daily subcutaneous (SC) injections of either agent until ANC levels reached at least 1500/microL. There was no statistical difference between treatment groups in the mean number of days to reach an ANC of 500/microL, but the mean number of days to reach ANC levels of 1000/microL and 1500/microL was approximately one day less in patients receiving filgrastim. Fewer patients in the sargramostim arm were hospitalized, and they had a shorter mean length of hospitalization, mean duration of fever, and mean duration of i.v. antibiotic therapy compared with patients who received filgrastim. Both growth factors were well tolerated. No patient was readmitted to the hospital after growth factor was discontinued. Sargramostim and filgrastim have comparable efficacy and tolerability in the treatment of standard-dose chemotherapy-induced myelosuppression in community practice.