Age hardening of paving grade asphalt is a major factor affecting the durability of bitumen pavement. In this research, 60/70 penetration grade asphalt is modified using Styrene Butadiene Rubber(SBR) in percentages by weight of asphalt ranging from 2 to 6% and 1% by weight of asphalt of an antioxidant namely 4.4. thio bis (6- tertiary butyl – m – cresol (TBMTBP). The antioxidant is used to delay the age hardening . Hot mixes asphalt using the virgin and modified asphalt samples are prepared and evaluated using Marshall test method . Fourier Transform Infra Red (FTIR) is used to analyze all samples of asphaltic materials. The results reveled that, the polymer increased the performance of hot mix and the antioxidant delayed the formation of carbonyl group which is formed as a result of asphalt aging. So, this type of modification is considered as an attractive solution for increasing the performance and the service lifetime of asphalt mix .