In this study, bitumen was modified with different percentages of SBS polymer and Zycotherm additive. Effect of SBS modification and Zycotherm additive in the bituminous concrete mixture was evaluated by Marshall Stability test and Indirect tensile strength test. Comparisons were made between different bituminous mixtures prepared by base bitumen, SBS modified bitumen and Zycotherm modified bitumen. SBS dosage in bitumen was kept 3, 5 and 7%. The Zycotherm additive dosage was kept same for all mixes i.e. 0.1%. Two types of aggregate i.e. limestone and riverbed were used for this study. Marshall Stability for 5% SBS modification has shown better results. Indirect tensile strength for the mixture containing 5% SBS has shown maximum tensile strength as compared to other mixes. Limestone aggregate has shown maximum stability and maximum tensile strength as compared to riverbed aggregate. Zycotherm additive has shown no effect on mechanical properties of bituminous concrete mixtures. It was finally concluded that best results were obtained by using 5% SBS in bitumen and limestone aggregate in bituminous concrete mixtures.