Fifty-five patients, initially diagnosed as having advanced high grade non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD) refractory to first-line treatment or in relapse, were treated with ifosfamide 6 g/m2, infused over 48 h, followed by mitoxantrone 12 mg/m2. The regimen repeated at three-weekly intervals. Of 32 patients with NHL evaluable for response, 10 (31 per cent) achieved complete remission and five partial remission, giving an overall response rate of 47 per cent. Two patients subsequently went on to bone marrow transplant (BMT)--one allogeneic and the other autologous. Of 17 patients with HD evaluable for response, six (35 per cent) achieved complete remission and six partial remission, giving an overall response rate of 71 per cent. Two of this group also went on to BMT (both autografts). The principal toxicity was neutropenia, though central nervous system changes were observed in 10 patients. Given the need to offer alternative treatment of patients in these categories, this combination (I-M) is clearly of value in relapsed patients especially where therapeutic options are limited because of previous multi-drug treatment.