In this study, in order to reveal the effect of different bioactive glass matrix on magnetic bioactive glass-ceramics (MBGCs), the interfaces between magnetite and three most often used bioactive glass systems, 80SiO(2)-15CaO-5P(2)O(5) (80S), 58SiO(2)-36CaO-6P(2)O(5) (58S), and 35SiO(2)-50CaO-7P(2)O(5)-7MgO-1CaF(2) (35SM), were prepared and analyzed. Moreover, the phase composition, magnetic structure, and in vitro reactivity of the corresponding glass/ferrite composites with 29 wt% ferrite were investigated. The results showed that Fe migrated into the glass matrix much faster than Si moved into the ferrite phase. Moreover, 58S and 80S glass displayed much stronger interfacial reactions with the ferrite than 35SM glass. Furthermore, the Mossbauer spectra revealed that the 35SM/ferrite composite, showing a saturation magnetization of 3.88 A center dot m(2)/kg, had about 29% Fe ions remained the magnetic structure and MgFe2O4 was detected, while all Fe ions were found to be in the paramagnetic structure in the other two composites. Additionally, continuous deposit layers covered all the three composite surfaces after being soaked in simulated body fluid for 14 days. Therefore, when used as MBGC glass matrix, the 35SM glass seemed to be more beneficial to the magnetism. The results of this study are helpful in the design and optimization of MBGCs.