The injectable hydrated calcium phosphate bone-like paste (hCPP) have been developed with suitable nanoscale characteristics and unindered injection through 23G standard needles. In vitro assays showed the cytocompatibility of hCPP with mesenchymal embryonic C3H10T1/2 cell cultures. The hCPPs were identified to be composed of aggregated nano-sized particles with sphere-like shapes with low crystallinity. The ability of serum proteins (FBS) to adsorb on hCPP particles was also studied. The hCPP demonstrated high protein adsorption capacity, thereby indicating its potential in various biomedical applications. The results of the in vivo assay upon subcutaneous injection in Wistar rats indicated the nontoxicity and biocompatibility of experimental hCPP, as well as the gradual resorption of hCPP, comparable to the period of bone regeneration. The data obtained are of great interest for the development of commercial highly effective osteoplastic materials for bone tissue regeneration and augmentation.