In this study, effort was focused on fabrication and characterization of nanostructure bioceramic composite foam. For this purpose, Hydroxyapatite (HA) and forsterite nanopowders were synthesized by sol-gel and mechanochemical method, respectively. Nanostructure composite foams were prepared via addition of the HA to forsterite, in proportion of 0, 10, 20 and 30 wt.% . X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy (TEM) were used to characterize and evaluate the phase structure, crystallite size, morphology, size and distribution of the pores, chemical composition and particle size of the prepared powders and nanostructure composite foams. The porosity of the foams was measured by Archimedes method. In order to evaluate the bioactivity and bioresorbability, the prepared foams were immersed in the simulated body fluid (SBF) for 28 days. The concentration of the calcium and phosphorous ions in the filtered solutions were determined by inductive coupled plasma optical emission spectroscopy (ICP-OES). XRD and SEM were used to investigate the bone like apatite formation on the surface of the foams and pores filling by formation of apatite. The results showed that the foams have a grain size smaller than 50 nm and pore size is in the range 60-400 ?m . The compressive strength and elastic modulus of the foams decreased with increasing of HA. The maximum values of compressive strength and elastic modulus of the foams were found to be about 7.2 MPa and 0.271 GPa, respectively, which are close to the lower limit of the compressive strength and elastic modulus of cancellous bone. The mean values of true and apparent porosity were calculated in the range 77-87% and 66-79%, respectively. In vitro tests showed the high bioactivity and resorbability of the foams. The obtained foams have similar chemical composition to the mineral phase of bone and by changing the ratio of HA/forsterite can approach the appropriate bioactivity and biodegradability level needed for different medical applications. Considering the obtained results, it seems that the manufactured foams could be a good candidate for tissue engineering applications such as drug delivery and cell loading. However, cell culture and in vivo tests are needed for more assurance. Keywords : Forsterite; Hydroxyapatite; Gelcasting; Nanostructure composite;