Tensile strength and per cent crystallinity of polybutylene-terephthalate (PBT) and acrylonitrile-butadiene-styrene (ABS) copolymer blends with 5% styrene-maleic-anhydride (SMA) as compatibilizer are determined. ABS content is varied in the range of 0-40%. The % crystallinity is determined using dynamic mechanical thermal analysis (DMTA) technique and the values are compared with those obtained using wide angle X-ray diffraction technique (WAXD). The tensile strength and % crystallinity are found to decrease with increasing ABS content, while tensile-strength increases with crystallinity.