The effect of styrene-ethylene-butylene-styrene (SEBS) copolymer on tensile properties, impact behaviours and fracture toughness of polycarbonate (PC) was studied. A decrease in tensile properties was observed where tensile strength decreases from 12 to 80 % while elongation-at-break decreases from 11 to 41 %. Notched Izod impact strength was enhanced significantly in presence of rubber and the blends became non-breakable at I broken vertical bar(d) = 0.21-0.40. Homogeneous dispersion of SEBS into the PC matrix was shown by morphological studies which indicate good affinity between the rubber particles and the polymer matrix. The dependence of impact strength on the blending rubber concentration and interparticle distance of the disperse phase were analysed. The fracture properties were studied by essential work of fracture method. It is revealed that non-essential or plastic work increase with an increased amount of SEBS.