The mechanical properties such as tensile behavior and impact strength of melt mixed poly(butylene terephthlate) (PBT)/acrylonitrile-butylacrylate-styrene (ABAS) terpolymer blends at ABAS contents up to 39 vol % were evaluated. Tensile properties decreased while impact strength was enhanced by the blending polymer. Morphological studies show good dispersion of ABAS into the PBT matrix. The strength properties were dependent on the crystallinity of PBT and interphase adhesion between the phases. The impact toughening was dependent on the blending rubber concentration and interparticle distance of the discrete phase. (c) 2007 Wiley Periodicals, Inc.