The main aim of this study was to determine an alternative for bitumen which will satisfy the physical and binding properties of bitumen in terms of strength, endurance, and flexibility. The asphalt market is looking for alternative sustainable binders that can fractionally replace the bitumen in terms of environmental sustainability and which may also augment the availability of binders. In this research study, crumb rubber has been consumed in bituminous mixes and its optimum content percentage is found, the crumb rubber is used in powdered form and that amount has been replaced from the quantity of bitumen. Standard Marshal Mix design and Penetration test and Ductility test were performed. The various percentages of crumb rubber (from 2% to 10% by the weight of bitumen) were used to prepare the samples, with optimum value of bitumen content (5%). It was observed that crumb rubber at 6% (by weight of bitumen) and at 5% Optimum Bitumen Content came out to be optimum percentage of crumb rubber. The test results shows that stability of the modified bitumen mix was increased as compared to the plain bitumen mix. The physical properties of modified bitumen were also improved, with the help of penetration test it was observed that the modified bitumen was harder consistency and was less flexible as per ductility test.