Tissue engineering using soft materials has become a very promising approach for repairing damaged cartilage and bone tissue. In this study, novel in situ forming composite hydrogels were synthesized based on chitosan and gelatin biopolymers associated with bioactive glass nanoparticles. The zeta potential at 37 degrees C ranged from + 3.1 +/- 1.4 mV to + 6.9 +/- 3.2 mV and showed the cationic nature of these hydrogels, which are capable of interacting with negatively charged molecules from native extracellular matrix (ECM). Moreover, the zeta potential analysis and FTIR spectra confirmed that network formation of the hydrogels occurs predominantly by molecular interactions. Rheological results revealed that the elastic modulus (G) increased from 5.4 Pa for pure chitosan hydrogels to 12.4 Pa for hydrogel composites with higher contents of gelatin and bioactive glass. Syringeability and injectability tests showed that all formulations can be smoothly expelled from a syringe and needle with the use of moderate force with a maximum value of 4.0 N. These hydrogel nanocomposites were cytocompatible based on the live cell viability responses of human osteosarcoma cell line (SAOS). These results suggest that these nanocomposites are a promising temporary injectable matrix for bone tissue engineering.