For bone regeneration in oral and maxillofacial surgery different bone graft materials (autologous, allogenic and synthetic) have been used. In recent years platelet-rich fibrin (PRF) has been considered suitable for bone regeneration. PRF is obtained from autologous peripheral blood by the separation of its constituents to produce activated fibrin based biomaterial to accelerate tissue healing. PRF contains high concentration of different platelets and leukocytes derived growth factors. Without adding any modifiers it is a totally autologous material prepared extemporaneously. A wide variety of centrifugation protocols for obtaining PRFs are available in the literature. Centrifugation parameters range from 600 rpm to 1200 or even up to 2400 with the centrifugation time from 3 to 12 or even 16 minutes. The aim of our study is to develop a protocol for obtaining liquid PRF that polymerizes in about 20-30 minutes and is a suitable matrix for the development of local drug delivery systems.