Twenty-three patients with acute non-lymphoblastic leukemia in relapse were treated with cyclophosphamide, fractionated total body irradiation (200 rad/day for six days) and allogeneic marrow transplantation. Six patients are alive in remission 756-1306 days following transplantation. One patient died of infection on day 17 without evidence of engraftment; all others achieved sustained engraftment. Eight patients died of recurrent leukemia, four of interstitial pneumonitis, two of infection, one of veno-occlusive disease of the liver and one of cardiac failure. The median survival time was 181 days.