Abstract: Polyester films with a good slitting property and good slipping property contain, in first and second embodiments, at least 0.005% by weight of calcium carbonate particles. The particle size S.sub.c of the polyester crystals, crystal face orientation index X.sub.i and the difference .DELTA.n between the refractive indices in the machine direction and in the transverse direction of the polyester film have a specific relationship, or the internal haze H, face orientation coefficient f.sub.n or the difference .DELTA.n between the refractive indices in the machine direction and in the transverse direction have a specific relationship. By satisfying the specific relationship, a good slitting property and good slipping property are obtained. A third embodiment provides a polyester film containing at least 0.005% by weight of calcium carbonate particles, which has a specific center line average roughness Ra, face orientation coefficient f.sub.n, the difference .DELTA.