Abstract: What is disclosed is a power transmission belt including a laminate composed of an adhesive rubber layer in which core wires are buried and a compressed rubber layer, to the periphery of which being adhered canvas, characterized in that the above-mentioned canvas is impregnated with an aqueous latex composition comprising 2-chloro-1,3-butadiene-2,3-dichloro-1,3-butadiene copolymer latex. The power transmission belt of the present invention does not necessitate any organic solvents and is excellent in thermal resistance, and especially has great adhesion force between the rubber layers and the canvas.