The objective of this project is to explore the effect of X-ray irradiation of thin polymeric films deposited at various substrate temperatures. pulsed laser deposition (PLD) technique is used for the deposition of PMMA thin films on glass substrate at 300 degrees C and 500 degrees C. These films have been irradiated with various X-rays fluences ranging from 2.56 to 5.76 mJ cm(-2). Characterization of the films (before and after the irradiation) is done with help of X-ray Diffractrometer, Optical Microscope, Vickers hardness tester and UV-vis spectroscopy techniques. From XRD data, it is revealed that ordered packing has been improved for the films deposited at 300 degrees C. However after irradiation the films exhibited the amorphous behavior regardless of the X-ray fluence. Film deposited at 500 degrees C shows amorphous structure before and after irradiation. Hardness and particle size of thin film have also increased with the increasing substrate temperature. However, the irradiation has reverse effect i.e. the particle size as well as the hardness has reduced. Irradiation has also enhanced the absorption in the UV-visible region. (C) 2012 Elsevier B. V. All rights reserved.