Acute lymphoblastic leukemia is highly sensitive to induction chemotherapy; however, long-term survival in adults has been less than 35%, primarily as a result of high relapse rate. Treatment for relapsed disease is even less successful. The optimal post-remission therapy in the first complete remission offers the best opportunity for leukemia-free survival. Allogeneic donor stem cell transplantation can offer a unique anti-leukemia effect and a potential for extended survival. We will discuss advances in unrelated donor (URD) stem cells transplantation, improvements in transplantation process and supportive care along with growing experience with umbilical cord blood (UCB) allografts.