Ball milling technique was applied to prepare binary mixtures of poly(ether imide) (PEI) with poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), and poly(ether ether ketone) (PEEK). From differential scanning calorimetry (DSC) and X-ray diffraction (XRD) measurements, we have analyzed the influence that PEI has on the thermal behavior of these mixtures. A comparison with the blends formed by conventional methods has been performed.