Six fractionated total body irradiation (TBI) regimens given over 2-7 days to a total midline dose of between 1200 and 1750 rads were evaluated in 41 patients with acute lymphoblastic leukemia in relapse. Cyclophosphamide 120 mg/kg was given prior to TBI in all cases, and dimethylbusulphan was added to cyclophosphamide and 1500 rad TBI in one regimen. Relapses occurred in all regimens. The overall disease-free survival of three of 41 patients was not different from previous studies with 1000 rad TBI given in a single dose. Graft-vs-host disease occurred in only 12 of 41 patients. Two of three disease-free survivors had significant graft-vs-host disease.