High doses of cytotoxic drugs may impair stem cell collection. Failure in stem cell collection by bone marrow aspiration can be rescued by harvesting Peripheral Blood Stem Cell (PBSC) after a combination of chemotherapy and hematopoietic growth factor. We, therefore, retrospectively evaluated the possibility of collecting PBSC after chemotherapy and/or G-CSF administration in 12 patients with insufficient Granulocyte-macrophage colony-forming unit (CFU-GM) counts after bone marrow aspiration (all patients had previously received heavy chemotherapy for hematologic malignancies); median collection of CFU-GM/kg count was 2,9 x 10(4)/kg (range 0,4 to 8 x 10(4)/kg) whereas the minimal count required for autografting is 10 x 10(4)/kg. Median collections of CFU-GM from PBSC were 5,8 x 10(4)/kg. While the CFU-GM collected in PBSC was higher than after bone marrow aspiration, only 5 patients had enough PBSC for autografting. In another case, addition of cells collected from both PBSC and bone marrow aspiration yielded a sufficient number of CFU-GM to allow autografting. Therefore in this selected and small group of patients, failure in bone marrow aspiration does not seem to be predictive of a low PBSC collection but a long therapy free interval and use of G-CSF alone for PBSC mobilization could constitute a valuable alternative. Three patients had a successful short term hematologic reconstitution out of the four patients having had an autograft.