Department of Polymer Chemistry, School of Chemical Sciences, North Maharashtra University, P.O. Box : 80, Jalgaon-425 00 I, India E-mail: alkadasinabii@Maktoob.com Fax: 91-257-2258403 Manuscript received 6 January 2005, accepted 12 July 2005 Attempts have been made for utilization of flyash as a filler in elastomers as it is a waste product of thermal power stations, generated in huge quantities and has been posing problems of disposal. It is used as a filler for rubbers and plastics to a very small extent. It has been established that flyash does not at all contribute in enhancing mechanical properties of composites. The purpose of this work was to make meaningful utilization of flyash as a filler, by treating it with silane coupling agent LICA 01 i.e. neopentyl (diallyl)oxy, trineodecanonyl titanate. Composites of styrene butadiene rubber (SBR) containing treated and untreated flyash were made with varying proportions. A two-roll mill was used for dispersing the filler in the rubber and compression molding technique was used to cure the compounded material in sheet form. Tensile properties were measured on a computerized UTM using ASTM procedure. Comparison of properties of composites filled with treated and untreated fly ash established that the treatment with flyash imparts better reinforcing properties. Tensile strength was improved by 13% while modulus at 400% and Young's modulus were improved by 198 and 17% respectively at the volume fraction (0.42).