Mobilization techniques for peripheral blood stem cell (PBSC) collection include the administration of chemotherapy followed by hematopoietic growth factors or growth factors alone. Two forms of recombinant human granulocyte colony-stimulating factor (rhG-CSF) are available for PBSC mobilization: lenograstim and filgrastim which are the glycosylated and non-glycosylated forms respectively. In order to determine the influence of the two forms of G-CSF following chemotherapy on PBSC collection, we conducted a retrospective study in 126 patients with various hematological malignancies: 65 and 61 for the lenograstim and filgrastim groups respectively. No significant differences between the two groups were observed in terms of sex, age and diagnosis. Prior therapies and PBSC mobilization regimen were also equivalent. No significant difference was observed between the groups for the median CD34+ cells harvested. The number of leukapheresis necessary to obtain a minimal number of 3 x 10(6) CD34+ cells/kg was equivalent for the two groups. The proportion of patients affected by a failure in PBSC collection was similar in the two groups. Our data suggest that lenograstim and filgrastim are equivalent for PBSC mobilization after chemotherapy.