Ifosfamide (2.0 g/m2 intravenously/day x 3) with mesna (400 mg/m2 intravenously q 4 h daily x 3) was combined with mitoxantrone (14 mg/m2 intravenously x 1) and given on a 3 week schedule to patients with previously treated non-Hodgkin's lymphoma. In 45 eligible/evaluable patients, a 47% response rate (95% confidence interval: 32%, 62%) was achieved of which 25% were complete responses and 22% were partial responses. Median duration of remission was 10 months with 42% of patients in remission at 18 months. Hematologic toxicity (granulocytopenia) was the dose-limiting toxicity with severe or life-threatening granulocytopenia in 98% of patients at full protocol doses. Nausea/vomiting was seen in 73% of patients but was usually mild/moderate. Three patients had significant hematuria secondary to ifosfamide. Two patients had severe changes in the left ventricular ejection fraction (LVEF) secondary to mitoxantrone; and one patient had acute neurologic dysfunction secondary to ifosfamide. Ifosfamide/mesna can be safely combined with mitoxantrone at full doses in previously treated patients with non-Hodgkin's lymphoma. This combination should be considered for other trials in lymphoma.