Successful stem cell mobilization and collection is possible in B-CLL after a favorable response to preceding chemotherapy, and also after treatment with the new nucleoside analogues fludarabine and cladribine. A poor response, on the other hand, seemed to predict a mobilization failure. CD34+ cell selection resulted in a 2- to 3-log reduction of the CLL cells in the harvests. Engraftment with both unselected and selected progenitor cells was rapid, and need for hospitalization was short. High-dose therapy with stem cell rescue appears to be capable of inducing CRs of high quality, but so far the follow-up is too short to define whether this will be translated into prolonged disease-free survival.