An experimental study was carried out to examine the compatibilizing effect of phenoxy resin for blends of aromatic polysulphones and polyalkylene terephthalates. Dynamic mechanical spectra did not reveal relaxation peaks associated with the phenoxy phase, while the relaxation peaks associated with the glass transition temperatures of the polyester and polysulphone phases were closer to each other than for the corresponding individual polymers, confirming that the phenoxy was totally dissolved in the two main polymer phases.Whereas the blends containing the butylene terephthalate polymers (homopolymer and block copolymer) exhibited a co-continuous two-phase morphology even at high concentrations of polysulphone, those based on polyethylene terephthalate revealed the presence of discrete particles. These two types of morphologies gave rise to large differences in mechanical properties and solvent resistance. The best properties were obtained with the systems characterized by a co-continuous two-phase morphology. Moreover, the systems based on bisphenol A polysulphones showed superior properties to the corresponding systems containing polyethersulphones.