The aim of this study is to investigate the impact of mobilization with granulocyte colony stimulating factor (G-CSF) and apheresis procedure on inflammatory and oxidative stress markers, and antioxidant capacity in healthy allo-HSCT donors. The study was conducted in the Stem Cell Transplantation Unit of Gazi University Hospital between October 2010 and March 2011, and 25 consecutive allo-HSCT donors were included. The alteration in the serum levels of iron, iron binding capacity, albumin, ferritin, IL-6, hs-CRP, TAC, MDA, and AOPP were determined at five different time points. (1) Prior to the first dose of G-CSF (T0), (2) preapheresis (on the fourth day of G-CSF before the apeheresis procedure) (T1), (3) immediately postapheresis (T2), (4) 24 h postapheresis (T3), and (5) a week after apheresis (T4). Serum ferritin levels increased steadily after administration of G-CSF and remained high up toT4. Both serum IL-6 and hs-CRP levels began to increase in the T1 sampling and reached to a maximum level at T3 and decreased even below the basal levels at T4. Serum AOPP levels decreased at preapheresis and postapheresis time points, while they increased at T3 and T4 samples. Serum MDA levels decreased at T1, T2, T3, and T4 samples. Serum TAC increased significantly and steadily at all time points post G-CSF. In conclusion; mobilization with G-CSF and apheresis caused a transient inflammatory reaction and a protein limited oxidative stress in healthy allo-HCT donors. J. Clin. Apheresis 30:197-203, 2015. (c) 2014 Wiley Periodicals, Inc.