Seven patients with acute nonlymphocytic leukemia (ANL) following therapy for Hodgkin's disease (HD) were treated with cyclophosphamide (Cy) alone or combined with 10.00 to 15.75 Gy total body irradiation (TBI) and marrow transplantation. Five patients were transplanted without an attempt at prior remission induction, one patient following failure of remission induction and one patient in first remission following successful induction. Four patients died of multiorgan failure, 15 to 70 days after transplant. Three patients died of progressive or recurrent leukemia 56, 120, and 280 days after transplant. These results illustrate the difficulty of treating patients for secondary leukemia with marrow transplantation and suggest that transplantation in the preleukemic phase should be studied.