||Rubber-soil is an innovative and environmental friendly geo-construction material, which incorporates rubber chips derived from scrap rubber tires with cementitious material into a lightweight geo-material. This innovative material displays very good geotechnical properties such as, high stiffness, high strength, free drainage, resiliency with excellent dynamic performance. Such properties could provide advantages for the material to use as sub-base layer for flexible pavement of highway road structure. In this study, a series of laboratory tests and in-situ field test were conducted to investigate the performance of Rubber Soil as flexible highway sub-base. A methodology for the construction of flexible highway pavement using Rubber-soil as sub-base layer was also proposed. This study will discuss the results obtained from the conventional small-scale laboratory tests and large-scale model experiment test, together with the results obtained from in-situ field test conducted on the trial test track site. From the conventional laboratory test results, it was found that Rubber-Soil can provide adequate stiffness with good material resiliency. It improves the load spreading mechanism of the flexible pavement and reduces the vertical stress at the sub-grade level and tensile strain developed at the asphalt concrete layer; hence the deformational problem on the sub-grade layer and the potential development for reflective cracks on asphalt layer can be reduced. By comparing the model panel test results of flexible pavement constructed with Rubber-soil sub-base with that using conventional Type I granular sub-base, it was found that Rubber-soil sub-base can reduce the maximum tensile strain developed at the asphalt layer of the pavement. Lower maximum tensile strain extends the fatigue life of the pavement material and restraint the fatigue cracking formation on the flexible pavement. From the in-situ field test, it was found that existing pavement construction equipment and methodology can handle the Rubber-Soil laying process efficiently. As a result of these findings, lower pavement maintenance cost is expected from the Rubber-Soil supported highway while the construction expenditure will not be increased with the use of the new material.