Infused CD34 cell count has a significant impact on transplant outcome. In this retrospective study, we aimed to analyze the impact of donor iron parameters on peripheral blood stem cell (PBSC) collection. A total of 303 related donors were included in the study. The mobilization regimen, recombinant G-CSF, was given for four consecutive days. A CD34+ cell count below 2×106/kg was defined as mobilization failure which was demonstrated in 23 donors (7.6%). Mobilization failure was more frequent in female donors than male donors (13.7% vs 3.4%). Body mass index, mean corpuscular volume, hemoglobin and ferritin levels were found to be lower in donors with mobilization failure. Body mass index was significantly correlated with PBSC count on the 4th day of G-CSF. Body mass index, male gender, mean corpuscular volume and ferritin levels had significant impact on PBSC count. Although PBSC count was found to be similar between female and male donors, female gender was shown to have an adverse impact on PBSC collection, which may be attributed to lower body weight and concurrent iron deficiency.