This work concerns with obtaining and characterization of new hydrogels based on sodium alginate and gelatin in the form of cross-linked polymer networks, aimed at medical applications, for example controlled release of bioactive agents (pharmaceutical industry) and bioinks (regenerative medicine). Our synthesis strategy was based on the use of mild, ecological reaction conditions in the absence of crosslinking agents and organic oxidants. Only industrially available sodium alginate and gelatin from leather wastes, produced at micro-pilot level at INCDTP-ICPI, were used, without the presence of any additional crosslinking agents, to test their ability to form strong 3D gels. Tunable physical-chemical and mechanical properties of the hydrogels have were obtained by varying the ratio sodium alginate: gelatin. Newly synthesized hydrogels were characterized by both analytical methods, such as ATR-FTIR, TG-DTG and SEM, and standard tests for mechanical resistance.