This paper describes the utilisation of flyash as a filler after being treated with silane coupling agent and used as fillers in NR. The properties considered were tensile strength, modulus at 100;and 400;, Youngs modulus and hardness. Composites were made with varying proportion of untreated and treated flyash. A two-roll mill was used for dispersing the filler in the rubber and compression moulding technique was used to cure the compounds in sheet forms. Tensile properties were measured on a computerised UTM using ASTM procedure. Comparison of properties of composites filled with treated and untreated flyash established that treatment of flyash imparted better reinforcing properties. Tensile strength improved by 83;while modulus at 400;improved by 100;and Youngs modulus improved by 29;. Similarly elongation at break also improved by 50;. The silane coupling agent used here promoted adhesion between flyash and NR.