A white porous polyester film of the present invention comprising a polyester-based monopolymer/copolymer blend, a crystalline polymer resin which is not miscible with a polyester and has a heat deformation temperature of 90° C. or higher, inorganic particles, a whitening agent, and a stabilizing agent has improved optical properties, and thus is useful as a film for use in printing, labeling, electronics, and display applications.