Objective Peripheral blood stem cell transplantation is frequently used in the treatment of various hematological malignancies after intensive chemotherapy. The primary aim of our study is to compare the amount of collected CD34+ cells and engraftment times in patients mobilized with filgrastim or lenograstim. Material and Methods Demographic and clinical data of multiple myeloma (MM) and lymphoma patients who underwent autologous transplantation and mobilized with G-CSF (filgrastim or lenograstim) without chemotherapy were collected retrospectively. Results One hundred eleven MM and 58 lymphoma patients were included in the study. When mobilization with filgrastim and lenograstim was compared in MM patients, there was no significant difference in neutrophil and thrombocyte engraftment times of lenograstim and filgrastim groups (p = 0.931 p = 0.135, respectively). Similarly, the median number of CD34+ cells collected in patients receiving filgrastim and lenograstim was very similar (4.2 x 10(6)/kg vs 4.3 x 10(6)/kg, p = 0.977). When compared with patients who received lenalidomide before transplantation and patients who did not receive lenalidomide, the CD34+ counts of the two groups were similar. However, neutrophil and platelet engraftment times in the group not receiving lenalidomide tended to be shorter (p = 0.095 and p = 0.12, respectively). When lymphoma patients mobilized with filgrastim and lenograstim were compared, neutrophil engraftment time (p = 0.498), thrombocyte engraftment time (p = 0.184), collected CD34+ cell counts (p = 0.179) and mobilization success (p = 0.161) of the groups mobilized with filgrastim and lenograstim were similar. Conclusion The superiority of the two agents to each other could not be demonstrated. Multi-center prospective studies with larger numbers of patients are needed.