Black cotton soils which are well known for their expansive nature are a worldwide problem posing many challenges to civil engineers, construction firms and owners. Stabilization of black cotton soils with different additive materials has likewise achieved great progress and on account of fast industrialization all through the world; the generation of enormous amount of waste materials creates ecological issue as well as disposal problems. Numerous methods have been developed by many researchers to enhance the mechanical properties of soil by incorporating an extensive variety of stabilizing materials. An attempt has been made in this paper to utilize Ground granulated blast furnace slag(GGBS), an industrial by product and polypropylene fibres as stabilizing materials. The impact of GGBS and polypropylene fibers on certain properties of soil, for example, Atterberg limits, compaction characteristics (MDD, OMC), Unconfined compressive strength (UCS) and Free swell had been examined. All the tests were performed on the samples by utilizing GGBS and 12mm polypropylene fibers. A series of UCS and Free swell tests were carried out on black cotton soil by varying percentage of GGBS (0%, 10%, 20%, 30%, 40% 50%, 60%) and polypropylene fibers of length 12 mm and proportions (0%, 0.25% 0.50%, 0.75%, 1.00%) by weight of dry soil with optimum percentage of slag). Results of various tests demonstrated the inclusion of GGBS and polypropylene fibers in soil with appropriate proportion improved strength and swelling behavior of soils.