The effect of solar radiation in the aging of the asphalt binder can be considered relevant in several countries due to the high level of insulation. This article deals with the comparative aging of a conventional asphalt binder and styrene-butadiene-styrene modified asphalt binder samples under the effect of weathering. The samples were exposed to cycles of xenon radiation, moisture, and temperature. The degradation of binders was analyzed by using the technique of Fourier transform infrared spectroscopy. The C?H/C?O ratio decreased 92.5% for the conventional asphalt cement and 74% for the polymer modified asphalt after 150 h of exposure in a weathering chamber. The oxidation resistance of styrene-butadiene-styrene modified asphalt binder was higher than the conventional asphalt cement evaluated by using the weathering test and infrared spectroscopy analysis. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012