There is a need to develop advanced multifunctional scaffolds for the treatment of bone tissue lesions, which apart from providing support for infiltrating cells could assure the delivery of drugs or biologically active molecules enhancing bone formation. We developed composite scaffolds for bone tissue engineering based on gellan gum (GG) and gelatin (Gel) hydrogel enriched with epigallocatechin gallate (EGCG) loaded CaCO3 microparticles and subjected to enzymatic mineralization with calcium phosphate (CaP). The method of manufacturing CaCO3 microparticles was optimized. The EGCG-loaded microparticles were smaller than those unloaded, and the release of EGCG was prolonged for up to 14 days, as shown by the Folin-Ciocalteu test. The particles reduced the viability of the MG-63 cells as compared to the control. However, when they were loaded with EGCG, their cytotoxicity was reduced. The particles were suspended in a GG/Gel hydrogel containing alkaline phosphatase (ALP), soaked in calcium glycerophosphate (CaGP) solution to create CaP deposits, and submitted to freeze-drying, in order to produce a porous scaffold. The microstructure of the scaffolds was characterized by optical and scanning electron microscopy and showed that the size of the pores corresponds to that of the spongy bone. In vitro tests with MG-63 cells confirmed that mineralized scaffolds support cell adhesion and growth to a higher extent than nonmineralized ones.