The aim of this study was to design and fabricate a series of cell-free porous scaffolds, based on chitosan/beta-tricalcium phosphate (CS/β-TCP) composite biomaterials, and evaluate their osteogenic potential in terms of ectopic bone formation in mice as a model animal. The scaffolds were fabricated by a coprecipitation process using the CS and β -TCP with different concentrations of hydrogen peroxide (H2O2) (1, 2, 4 and 8%) as a porogen. This process gives rise to a series of porous scaffolds with different levels of porosity. The scaffolds were subjected to evaluation for their porosity, pore size and water absorption ability. It was found that the pore sizes of the CS/β TCP scaffolds were larger with the increase of concentration of H2O2. The biocompatibility and osteogenic potential of the scaffolds were evaluated by implanting them intramuscularly in mice. The samples were harvested 8 weeks post-surgery to assess ectopic bone formation. The formation of new bone tissues was observed only in 2% and 4% H2O2 groups in vivo, and area percentage of new bone formation was measured by a modified slice-by-slice approach. The results of this study revealed that the porosity plays a major role in bone formation and optimization of the porosity/pore size of the scaffolding system is essential to trigger their osteogenic potential. © 2021 by American Scientific Publishers.