Peripheral blood progenitor cells (PBPCs) have become the major source of hematopoietic progenitor cells for allogeneic transplantation. In February 2008, Zarzio® was approved by the European Medicine Agency for PBPCs mobilization, but this authorization was not based in trials analyzing safety and efficacy for PBPCs mobilization. Since August 2011, Zarzio® has been used at our institution for PBPCs mobilization. In total 36 healthy family donors underwent PBPCs mobilization, 18 with Neupogen® and 18 with Zarzio®. Donor characteristics were equivalent between groups, and no severe adverse effects were registered in the Zarzio® group. The number of CD34 cells collected/Kg recipient body weight was 6.7 × 10(6) (3.8-11.1) in the Zarzio® group versus 8.4 × 10(6) (5.6-16.6) in the Neupogen® group (P = 0.04). We collected the minimal target cell dose (2 × 10(6) /kg) in all donors from each group and no significant differences were found in the collection of the optimal cell dose (5 × 10(6) /kg) between groups, although 3/18 (16.6%) donors that received Zarzio® failed to mobilize the optimal cell dose compared with 0% in the Neupogen® group. A total of 35 patients proceeded to transplantation (17 in the Zarzio® and 18 in the Neupogen® groups, respectively). Platelet and neutrophil median time to engraftment was comparable between the two groups. Our retrospective study supports the conclusion that Zarzio® mobilization of PBPCs in healthy donors is safe but perhaps not as effective as the reference Neupogen. However, more prospective trials are required to definitively asses the safety and efficacy of G-CSF biosimilars for PBPCs mobilization in healthy donors.