This study evaluated the effect of filgrastim (granulocyte colony-stimulating factor [G-CSF]) on the duration of granulocytopenia and thrombocytopenia after intensive consolidation therapy with diaziquone (AZO) and mitroxantrone for patients less than 60 years of age with acute myeloid leukemia (AML) in complete remission. Patients less than 60 years of age with AML who achieved complete remission (CR) with daunorubicin and cytarabine induction therapy, were scheduled to receive three sequential courses of high-dose cytarabine, cyclophosphamide/etoposide, AZQ, and mitroxantrone in a pilot study to determine their tolerance of these three sequential consolidation regimens. The initial patients treated with AZQ and mitroxantrone experienced prolonged bone marrow suppression and, therefore, subsequent cohorts were treated with G-CSF, 5 micrograms/kg, beginning the day after completion of the third cycle of chemotherapy. There was a marked decrease in the duration of granulocytopenia less than 500/microL in two groups of patients receiving two different dose levels of AZQ and the same dose of mitoxantrone compared with patients not receiving the G-CSF. There was also a decrease in the need for hospitalization, as well as the duration of hospitalization. There was a trend towards shortening of the duration of thromobocytopenia, as well. The duration of complete remission and overall survival was similar in patients who received or did not receive G-CSF. G-CSF markedly shortened the duration of granulocytopenia in patients with AML receiving intensive postremission consolidation with AZQ and mitoxantrone. There was no adverse effect on CR duration or survival.