In the present work the effect of doping 1% nano-sized diamond particles on the structure and properties of biocomposites (sintered at 500 and 780 ºC on air) based on biogenic hydroxyapatite and sodium silicate glass were investigated. Volume and mass shrinkages of composites after sintering, their phase composition, microstructure, porosity, mechanical and bioactivity properties were studied. According to the XRD results it was established that sintering temperature and diamond doping does not effect on the phase composition of the biocomposites and only hydroxyapatite phase Ca5(PO4)6(OH) was detected. SEM investigation showed a complex morphology of samples surface and more rounded particles in agglomerates for biocomposites sintered at 500 ºC compared to biocomposites sintered at 780 ºC. The total porosity of the samples depends on the sintering temperature and the doping and is equal to 37-44 %. Experiments in vitro showed solubility of biocomposites in saline at 36.5±0.5 ºC and their mass loss in the first 2 days. Dissolution rate is equal to 0.42-0.78 wt.%/day depending on the sintering temperature and the doping of materials. It was found that doping nano-sized diamond 2 times increases the mechanical strength of biocomposites.