Twenty-three children with refractory or relapsed non-Hodgkin's lymphoma (NHL) received high-dose methotrexate (HD-MTX), and 9 received Ara-C by continuous intravenous infusion, as phase II studies. They all had previously received a protocol including vincristine, adriamycin, cyclophosphamide, IV push Ara-C, asparaginase, intrathecal MTX, and cranial irradiation, and had failed to respond or had relapsed. HD-MTX was given at the dose of 6 g/m2 or more with leucovorin rescue, Ara-C at the dose of 100 mg/m2/day by continuous infusion over 10 days. Among the 22 evaluable patients receiving HD-MTX, 10 responses (7 CR; 3 PR) were observed. Among the 9 patients receiving Ara-C, 4 responded (1 CR; 3 PR). Toxicity in those previously heavily treated patients was acceptable. These two drugs are now successfully included in childhood NHL treatment protocols.