A biaxially-oriented polyester film includes at least two layers and at least one outermost layer is composed of a polyester having a rigid amorphous content of about 10 to 55%. The biaxially-oriented polyester film has a longitudinal Young's modulus of at least about 4.5 GPa. The biaxially-oriented polyester film is suitable for high-density magnetic recording media, such as digital video tapes and high-density data recording tapes.