This paper provides analysis of the chemical composition of two asphalt binders that were subjected to various environmental factors (i.e., oxygen, heat, ultraviolet radiation, and moisture) in an accelerated weathering tester. The analysis was performed with the aid of Fourier transform infrared and X-ray photoelectron spectroscopy. The results were compared to those obtained for asphalt binder samples that were subjected to the same protocol but in the absence of moisture. The concentrations of oxygen, nitrogen, and sulfur increased with exposure (or aging) time on the surface of the binder samples that were aged without moisture. However, in the presence of moisture, these elements increased initially and then remained constant or decreased as time progressed in the weathering tester. This was attributed to the solubilization and removal of the superficial aged binder by water, which continuously exposed an unaged surface.