Purpose: The aim of this study was to compare a new method for the production of platelet-rich plasma (PRP), the plasma-rich-in-growth-factors kit (PRGF kit; G.A.C. Medicale San Antonio, Vitoria, Spain), with an established method, the Platelet Concentrate Collection System (PCCS; 3i/Implant Innovations, Palm Beach Gardens, FL) with respect to resulting cellular and growth factor contents. Materials and Methods: Whole blood was drawn from 51 healthy donors (20 men, 31 women) aged 19 to 59 years (mean ± SD 35.12 ± 9.65 years), and PRP was prepared by both methods. Results: Platelet counts differed significantly (signed rank test, P .001 for all) between the donor blood (274,200 ± 54,050/µL), the PCCS PRP preparation (1,641,800 ± 426,820/µL), and the PRGF kit PRP preparation (513,630 ± 139,470/µL). The PCCS concentrated leukocytes (whole blood, 6,992 ± 2,011/µL; PCCS PRP, 14,153 ± 7,577/µL), while the PRGF kit produced a leukocyte-poor PRP (65 ± 108/µL). Higher concentrations of transforming growth factor ß1 (TGF-ß1) and platelet-derived growth factor AB (PDGF-AB) were found in the PCCS PRP (TGF-ß1, 290 ± 95 ng/mL; PDGF-AB, 157 ± 62 ng/mL) than in the Anitua PRGF kit PRP (TGF-ß1, 73 ± 26 ng/mL; PDGF-AB, 47 ± 21 ng/mL). Statistical analysis showed significant differences (P .001 for TGF-ß1 and P .01 for PDGF-AB). Discussion: The results of this study and some data in the literature indicate that the content of growth factors in PRP can vary tremendously, depending on the system used for the preparation of PRP. Conclusion: PCCS collects more platelets and leukocytes than the PRGF kit. This results in significantly higher growth factor levels. Further in vivo studies are needed to determine whether this results in a clinically different biologic effect.