A carbon fiber cord for rubber reinforcement comprising a carbon fiber bundle having coated thereon from 5 to 50% by weight, based on the total weight of the carbon fiber bundle thus treated, of a resin composition comprising a mixture of 100 parts by weight of a butadiene-acrylonitrile copolymer having a carboxyl group on at least both terminals of the molecule of the copolymer and from 5 to 40 parts by weight of an epoxy resin, or a reaction mixture obtained therefrom, and a curing agent for the epoxy resin, and further coated thereon from 0.5 to 5% by weight, based on the total weight of the carbon fiber bundle and the resin composition coated thereon, of a mixture of a phenolformalin-rubber latex type adhesive for rubber. The carbon fiber cord exhibits excellent adhesion to rubber and fatigue resistance.