Bone cements are used in orthopaedic surgery and dentistry, and the commonly used commercial ones are prepared from poly (methylmethacrylate) (PMMA). In orthopaedic surgery bone cements are used as filling agents for the treatment of damaged tissues and they are used to stabilize the prosthesis by providing the mechanical interlock between bone and metal during the use of metal prothesis and to provide the homogeneous distribution of applied load. In this study, bone cements compositions were prepared by using two different PMMA (microspheres prepared by suspension polymerization and ground and sieved PMMA particles). Compositions were prepared by addition of hydroxyapatite (HA) as inorganic load carrying substance, and barium sulphate (BaSO4) as opacifier. To increase biocompatibility of the prepared bone cements, natural polymer chitosan was added. It was observed that addition of chitosan had a positive effect on mechanical properties.