Human peripheral blood obtained after chemotherapy-induced remission in hemopoietic malignancies has been suggested to be a potential substitute for autologous bone marrow as regards autologous hematopoietic reconstitution. The schedule and consequences of early leukapheresis are, however, still imprecise. We report a study performed in two series of, respectively, 10 and 14 patients where sequential leukapheresis (total number = 84) was evaluated with regard to colony-forming unit (CFU) potency. Our data demonstrate that adequate numbers of progenitor cells can be collected by leukapheresis and that, even when this is performed at an early stage after remission, subsequent hematopoietic reconstitution is not impaired.