In this study, we analyzed the effects of varying concentrations of chitosan (CS) and beta-tricalcium phosphate [beta-TCP, Ca3(PO4)2] on the mechanical and cell-adhesion properties of a collagen (CG) matrix for use in guided bone regeneration (GBR). Three different CS concentrations (0.5, 1, and 2%) and five different contents of beta-TCP (0, 17, 29, 38, and 44%) were investigated. The composite membranes were analyzed by scanning electron microscopy and cell-adhesion, flexural-strength, and tear-strength assays. The results show that the cell-adhesion and mechanical properties of the composite membranes improved with increasing beta-TCP and CS contents, yielding suitable levels of the adhesion of cells and adequate mechanical stability to ensure successful GBR. The CS adhered to the microsized beta-TCP, which was distributed uniformly in the composite membranes. The beta-TCP and CS have no negative effect on the cell morphology, viability, and proliferation and possess good biocompatibility. This study demonstrates that beta-TCP/CS/CG composite membranes are good candidates for GBR membranes in future applications. (C) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.