X-ray induced photo and Auger electron spectroscopic techniques have been used to characterize the surface composition of biaxially oriented polypropylene sheets with and without corona discharge treatment. The surfaces of polypropylene sheets without corona treatment contain very small amounts of 0 and the C 1 s peak is narrow, consisting mainly of -CH groups and less than 5% -C-O groups. After corona treatment the intensity of the 01s peak increases by a factor of 8, the Cls peak broadens and -C-O intensity increases by a factor of 3. The surfaces of aluminized polypropylene contains both aluminium oxide and metallic aluminium. From the measured intensity ratio of the A13’/A10 peaks the thickness of the oxide layer is estimated to be smaller than 4 nm. Aging increases the carbon content of the surface without changing the aluminium oxide/ metal composition. 0 1997 Elsevier Science B.V.