<p>Titanium (Ti) and its alloys are widely used in orthopedic and dental implants; however, implant failure remains a challenge due to the lack of chemical bonding between the implants and the host bone, which can lead to implant loosening. This issue can be addressed by introducing a bioactive layer that promotes chemical bonding to the bone upon implantation. This study is focused on the application of bio-inspired bioactive layers of calcium titanate (CaTiO₃) and calcite (CaCO₃) on Ti through a hydrothermal method. The initial CaTiO₃ layer acts as nuclei for further crystal growth of CaCO₃. The coating was obtained by treating Ti in a mixture of calcium acetate (Ca(CH₃COO)₂·H₂O) and NaOH, both with and without the addition of tartaric acid (C₄H₆O₆, TA). TA was a surface modifier to control coating composition and morphology. The morphology features, wettability, adhesion strength, and the interfacial structure between the Ti and the coatings were investigated. In addition, the biocompatibility of this biphasic coating with MC3T3-E1 osteoblast-like cells was initially studied. The coating layer consisted of CaTiO₃ and CaCO₃ biphasic coating, regardless of the presence of TA. The presence of TA in the coating solution significantly influenced morphology, crystallinity, surface interface, and in vitro cellular response. Cubic calcite crystals were unevenly deposited on the Ti substrate, whereas the substrate showed complete coverage with rod-like crystals and a more homogeneous microstructure with TA modification. In addition, transmission electron microscopy (TEM) indicated a firmly adherent mesoporous CaTiO₃/CaCO₃ to the Ti substrate. Consequently, the bioactive coating with TA modification exhibited higher cell numbers with flattened cell morphology than the surface without TA, as observed with MC3T3-E1 osteoblast-like cells.</p>