Plate type specimens were prepared by the injection molding of rubber modified plastics such as acrylonitrile-butadiene-styrene terpolymer (ABS resin) and acrylonitrile-acrylic elastmer-styrene terpolymer (AAS resin). With these specimens the effect of the orientation of rubber particles in these resins on their strength anisotropy was examined. It was found from the experimental results of strength anisotropy that spots with strong anisotropy of tensile strength inside the molding plate tended to show lower dart fall impact values. It was also found that the orientation showing high tensile strength at each measuring spot coincided nearly with the orientation giving the biggest cracks in the dart fall impact tests. An examination was also made on the relationship between the orientation of rubber particles and the anisotropy of the tensile strength, or the dart fall impact value. The results showed that the anisotropy of the tensile strength increased and the dart fall impact value decreased as the orientation of rubber particles increased. Further more, it became clear that the effect of the rubber particle orientation on the strength differed with the kind of resins and that the AAS resin was less affected by the orientation than the ABS resin.