The present invention relates to a polyester composition excellent in transparency, thermal stability, and flavor retention or excellent in transparency, thermal stability, flavor retention and gas barrier properties, which is obtained by blending a partially aromatic polyamide to a thermoplastic polyester, and also relates to a packaging material comprising the same. The polyester composition of the invention preferably contains an alkali metal atom in an amount of 0.1 to 300 ppm and phosphorus atom in an amount of 5 to 200 ppm. Further, it is preferable that the Color-L value of the molded article obtained by injection molding of the polyester composition of the invention at a molding temperature of 290° C. is 80.0 or more and the haze thereof is 20% or less. As the partially aromatic polyamide, an m-xylylene group-containing polyamide is preferable.