Ceramics, with basic composition based on the CaO-SiO2-P2O5-MgO system with different Ca+ Mg/P+Si molar ratio (R), were prepared via polystep sol-gel technique. The structure of the obtained ceramic materials has been studied by XRD, FTIR spectroscopy, and SEM. X-ray diffraction showed the presence of akermanite and HA for the sample with R = 1.68 and Mg substituted β-TCP and silicocarnotite for the sample with R = 2.16, after thermal treatment at 1200°C/2 h. The obtained results are in good agreement with FTIR. In vitro test for bioactivity in static condition proved that the carbonate containing hydroxyapatite (CO3HA) can be formed on the surface of the synthesized samples. CO3HA consisted of both A- and B-type CO 32− ions. SEM micrographs depicted different forms of HA particles, precipitated on the surface after soaking in 1.5 simulated body fluid (SBF).