Objectives: The aim of the present study is to evaluate the released residual monomers from composite resins that contain different proportions of bioactive glass (BAG). Methods: Experimental resin composites were prepared by a resin matrix (50% BisGMA and 50% TEGDMA) and inorganic filler with BAG (5, 10 and 30%). Each resin composite was placed in the tooth cavity (n=5). After polymerisation, samples were immediately immersed in 75% ethanol and 25% deionised water (6ml) at 37 degrees C. Residual monomers (Bis-GMA, TEGDMA, HEMA and UDMA) that were eluted from the composites for 10m, 1h, 1 d, 7 d and 30 d were analysed by high-performance liquid chromatography (HPLC). The data were analysed with one-way ANOVA and Tukey HSD at a p<0.05 significance level. Results: Among the time periods, the fastest released residual monomer was observed in the 10m elution. The highest amount of released residual monomer from all groups (except the control group) was TEGDMA, whereas this was HEMA for the control group. The amounts of residual monomers eluted from BAG30 were significantly higher than other groups (p<0.05). Conclusions: The release of the monomer increases in accordance with the increased BAG addition to the composite resins.