In this protocol, patients with lymphoid or hematologic malignancy receive induction therapy (fludarabine and EPOCH) and transplant chemotherapy (fludarabine and cytoxan) to deplete host T cells that mediate graft rejection. In our initial NCI cohort receiving HLA-matched sibling, G-CSF mobilized PBSCT on this protocol (n=19), graft rejection was prevented in all cases, with most recipients having 100% donor chimerism by day 28 post-SCT. With this reduced intensity regimen, GVHD remained a significant complication, with 6/19 recipients having grade II and 6/19 recipients having grade III acute GVHD. Importantly, potent graft-versus-tumor responses were observed, with 9/19 patients remaining in complete remission at a median of 17 months post-SCT.