In a recent phase I study, a combination of gemcitabine at 10 mg/(m(2)min) for 12 h and mitoxantrone 12 mg/m(2) daily for 3 days, achieved a complete remission (CR) in 3 of 12 (25%) patients with refractory leukemia. A pilot assessment of this regimen was conducted to determine its tolerability in patients with refractory acute myeloid leukemia (AML). In a cohort of 18 patients with very refractory disease (6 primary refractory, 12 relapsed, mean initial CR duration 3.5 months), one patient achieved a CR, a second CR with incomplete platelet recovery (CRp). Sepsis and mucositis were significant extramedullary toxicities. The gemcitabine and mitoxantrone regimen was feasible to administer even in heavily pre-treated patients. It was not active in patients who had failed a prior salvage regimen. It may warrant further study in patients with primary resistant AML.