A belt with a tensile cord embedded in an elastomeric body, having an adhesive composition impregnating the cord and coating the fibers. The adhesive composition is the reaction product of a polyisocyanate and a polyol, or a polyurethane prepolymer derived therefrom, and a polyamine curative and optionally additional polyol, and with optionally added plasticizer. At least one of the polyisocyanate, the prepolymer, and the polyamine are blocked with a blocking agent. The belt body may be of cast polyurethane, vulcanized rubber, or thermoplastic elastomer. The cord may have an adhesive overcoat.