The modulus and hardness of poly(ethylene terephthalate)(PET) and poly(ethylene naphthalate)(PEN) films are studied as a function of the uniaxial draw ratio using nanoindentation and macro-scale tensile testing equipment. Nanoindentation tests were conducted in the machine-transverse plane, the transvers-normal plane, and the machine-normal plane of the PET and PEN films to determine mechanical properties (hardness and modulus of elasticity) of the uniaxially stretched films at the nano-scale. The films were then re-tested using a tensile tester to determine the modulus on the macro-scale. The results from the two methods show large differences. Birefringence measurements indicate that the macro-scale and nano-scale moduli are strongly influenced by the chain orientation after uniaxial stretching. In addition, the influence of chain orientation is found to be much larger on the macro-scale than on the nano-scale.