Mobilized peripheral blood prognitor cells (PBPC) are increasingly being used instead of bone marrow for allogeneic transplantation. The present article will briefly review important aspects of allogeneic PBPCT including, donor safety, timing of leukapheresis, factors influencing the yield, cellular composition of PBPC allografts, hematopoietic capacity of allogeneic PBPC, and graft-versus-host and graft-versus-leukemia activities. It will particularly focus on the perspectives opened by PBPC for graft engineering and cell therapy.