The present invention is directed to a rubber composition comprising a diene elastomer, a reinforcing white filler, and a (white filler/elastomer) coupling agent, which is bifunctional and which can be bonded to the elastomer by means of a function X. The coupling agent X function is an ester function of an unsaturated .alpha.-.beta. acid bearing a carbonyl group on its .gamma. position and having the general formula (X): ##STR00001## where R, R.sup.1 and R.sup.2 may be the same or different, where R is a monovalent hydrocarbon radical, and where R.sup.1 and R.sup.2 may be a hydrogen atom or a monovalent hydrocarbon radical. The rubber composition of the present invention is useful for the manufacture of tires or semi-finished products for tires, such as tire treads.