We examined the short-term efficacy and toxicity of high doses of intravenous deferoxamine (DFO) in children with recurrent neuroblastoma. Ten children (3 2/12-20 years, median 6 5/12 years) had measurable recurrent disease following 1-3 prior treatment regimens. DFO (120-240 mg/kg/d) was planned as a continuous i.v. infusion for five days every other week. Serum ferritins at the start of this therapy ranged from 133-->5000 ng/ml (median 611 ng/ml). Of eight patients begun at a dose of 120-150 mg/kg/d, a single patient experienced visual disturbances which resolved after DFO was discontinued. Two patients begun at 240 mg/kg/d (with serum ferritins levels of 505 and 717 ng/ml) both experienced dose-limiting toxicity including lethargy, dizziness, blurred vision and leg cramps. Although decreases in serum ferritin levels of a least 10% were noted in 4 patients, there were no partial or complete response. DFO given at a dose of 150 mg/kg/d i.v. according to this schedule appears to be ineffective as a single agent against neuroblastoma. Starting doses of 240 mg/kg/d have unacceptable short-term toxicity.