In this study fracture toughness of bio-active glass ceramic materials is studied. Palmqvist and radial-median (halfpenny) crack equations were used to identify the fracture toughness of studied material. In the study the agreement of fracture toughness equations with experimental results of three point bending tests of bio-active glass ceramics is investigated. The fracture toughness of bio-active glass ceramics was calculated with 16 different equations in literature and illustrated with experimental results in the figures to identify most suitable equation for bio-active glass ceramics. Required data for equations were obtained from experimental Vickers rnicro-hardness tests. Although the fracture equations that are referenced with the number of 2-16 in the study are relatively in agreement with experimental results, the equation I has given the best agreement.