The aim of the study was the synthesis and characterization of bioactive osteoinductive glasses, in the SiO2 – CaO – P2O5 system. In order to maintain the bioactive character of bioglasses, for SiO2 contents higher than 60%, the sol – gel method was used for preparation. On the obtained powders, thermal, grain size and X - ray diffraction analysis were performed. The X - ray diffraction emphasized the formation of phosphate phases, whose proportion decreases as the silica content is increased. Later, the powders were thermally treated at temperatures between 1000 and 14000C, the phase composition evolution being monitored through XRD analysis. On the powder suspensions in physiological serum, the evolution of pH was investigated, in order to establish the chemical stability. The behavior of the obtained powders in physiological medium was studied, by immersing samples in simulated body fluid and excerpted after different periods of time.