Shear strength of soil is an important parameter for foundation and retaining wall design, and stability analysis of soil slopes in construction. Black cotton soil has swelling and shrinking characteristics, which tend to have low shear strength of soil. Several stabilization methods exist for improving strength characteristics of black cotton soil. The investigation was carried out to study the impact of silica fume with polypropylene fiber on the enhancement of strength characteristics of black cotton soil. The silica fume of 5%, 10%, 15% and 20% and polypropylene fiber of 0.5%, 1.0%, 1.5%, and 2.0% were blended with soil and experiments were conducted. The results indicated that the swelling potential characteristics were reduced considerably with addition of 20% of silica fume and 1.5% of polypropylene. The unconfined compressive strength (UCS) of soil was improved significantly with the addition of 20% of silica fume and 1.5% of polypropylene fiber.