Blends of semicrystalline isotactic polypropylene homopolymer and polypropylene copolymer with polybutylene terephthalate with different compatibilizers [i.e., styrene acrylonitrile, Surlyn, styrene- ethylene- butadiene styrene (SEBS), block copolymer and SEBS block copolymer grafted with maleic anhydride] were prepared by melt blending. Wide angle-X-ray scattering patterns of injection moldings were obtained. The crystallinity index and d-spacing were calculated with different concentrations of different compatibilizers. X-ray results in the structural investigation of the compatibilized blends correlated well with the different compatibilizer concentrations.