The low-density polyethylene (PE)/waste paper composites with different components ratio were prepared by extrusion. The photochemical stability of these samples and crystallinity degree of PE in blends were studied using ATR-FTIR spectroscopy. The thermal properties of composites were estimated by thermogravimetric analysis. Moreover, the morphological changes were observed by SEM. It was found that after long-term exposure to UV (100 h) composites undergo more efficient photo-oxidative degradation when compared with pure PE. Also the thermal stability of composites obtained is lower than that in PE. The results indicate that such a material is characterized by high susceptibility to environmental decomposition. (c) 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2197-2206, 2007