Blends of the polyhydroxyether of bisphenol-A (Phenoxy) and a series of ethylene terephthalate (ET)-caprolactone (CL) random copolyesters (TCL) having different ET contents were examined mainly by differential scanning calorimeter (DSC). A miscibility limit specified by the ET content was obtained and estimated to be about 90 wt%. When the ET content is less than this limit, the Phenoxy and copolyesters are miscible with each other. A relatively stronger specific intermolecular interaction between Phenoxy and copolyester was detected by Fourier Transform infra-red (FTIR) spectroscopy, and it may be an important factor which affects the miscibility in these blends. Based on the miscibility behaviour of Phenoxy/TCL copolyester blends, the factors which affect the miscibility of Phenoxy with polyester was discussed.