Mobilization regimen choice is a significant contributing factor for successful hematopoietic progenitor cell (HPC) collection by leukocytapheresis and reaching the target CD34+ cell dose. How mobilization regimen affects collection efficiency and the quality of products collected using the Spectra Optia apheresis instrument is not fully known. We evaluated the impact of granulocyte-colony stimulating factor (GCSF) and GCSF/plerixafor mobilization regimens on CE and product composition. We studied 373 leukocytapheresis HPC collections for 147 autologous transplants from January 1, 2010 to December 31, 2014. Patients were categorized in two groups; good mobilizers, mobilized with GCSF only (GM) and poor mobilizers, mobilized with GCSF and Plerixafor (PM). Overall, compared with PM group, total nucleated cell (TNC) yield was significantly lower in GM group (P = <.001). In contrast, median percent mononuclear cell (MNC) collected from GM (86.5%) was significantly higher than products collected from PM group (79.5%; P < .001). Compared with GM group, CD34+ cell CE was about 10% lower in PM group (P < .008). In addition, daily CD34+ cell/Kg yield was significantly higher in GM (2.08 × 10/Kg) compared with PM group (1.64 x 10/Kg, P = .019). Overall, the median number of collections per patient was two for GM and three for PM (P = .004). Products collected from PM group contained higher TNC content relative to GM group but had lower MNC enrichment, CD34+ cell CE and daily CD34+ cell yield per Kg. © 2018 Wiley Periodicals, Inc.