Aim: Tissue injury leads to platelets migration and release of growth factors (GF): Platelet-Derived GF (PDGF) and Transforming GF-beta (TGF-b) that are particularly important for the bone repair process. The purpose of our study is to evaluate the new bone formation with the use of AGF-bone graft combination and to estimate the concentrations of PDGF-AB and TGFb2 during the procedure. Methods: AGF-bone graft combination was used in19 patients with long bone defects (11) and spinal fusion (8). TGF-b2 and PDGF-AB concentrations were assessed in samples from blood. Aliquots were taken at each stage of AGF preparation (whole blood, buffy coat, AGF, wound drain) and analyzed for TGF-b2, PDGF-AB concentration and platelet counts. ELISA was performed to quantify concentrations of active PDGF-AB and TGF-b2. Results: Mean follow up time was 9 months. Signs of bone union were apparent in radiographs 3–6 months after the index procedure. Average platelet count increased from 212x106 cells/ml to 680x106 cells/ml (buffy coat) and to 1280x106 cells/ml (AGF concentrate), resulting in a 604% increase. A 480% increase of PDGF-AB levels and a 320% increase of TGFb2 levels in AGF concentrate comparing to whole blood levels was determined. TGF-b2 and PDGF-AB levels were also detected in samples collected from the wound drains, in increased levels comparing to the AGF concentrates. Conclusions: In all cases the clinical results were very encouraging with augmented osteogenesis, whereas the laboratory results (increased values of TGF-b2 and PDGF-AB in subsequent stages of the procedure) practically predicted the clinical success.