A method for producing a high strength flexible composite hose, and a hose produced by the method. The method includes forming a hollow inner core of uncured thermosetting elastomeric material. One or more layers of reinforcement material are applied to the outer peripheral surface of the uncured core. The uncured core and the reinforcement material are then encapsulated with a thermoplastic elastomeric cover while maintaining the temperature of the core below its vulcanization temperature. The temperature of the core and reinforcement material and cover is then increased to and maintained at a temperature which is at least as great as the vulcanization temperature of the core but less than the melting temperature of the cover for a time sufficient to vulcanize the core. The cover material has a smaller coefficient of thermal expansion than the uncured core material, and the cover material has sufficient tensile strength at the core vulcanization temperature to prevent localized plastic strain of the cover and to prevent the core from bleeding through the cover. The thermoplastic elastomeric cover thus provides a mold for the core and reinforcement material to maintain the shape of the core during vulcanization, and provides a permanent protective sheath for the completed hose after vulcanization.