A process for the production of a coated cemented carbide alloy having jointly a high toughness and high wear resistance is characterized by specifying the cooling rate during sintering in efficient manner. The alloy so produced comprises a cemented carbide substrate consisting of a hard phase of at least one member selected from the group consisting of carbides, nitrides and carbonitrides of Group IVa, Va and VIa metals of the Periodic Table and a binder phase consisting of at least one member selected from the iron group metals, and a monolayer or multilayer, provided thereon, consisting of a least one member selected from the group consisting of carbides, nitrides, oxides and borides of Group IVa, Va and VIa metals of the Periodic Table, solid solutions thereof and aluminium oxide, in which the hardness of the cemented carbide substrate in the range of 2 to 5 µm from the interface between the coating layer and substrate is 800 to 1300 kg/mm² by Vickers hardness at a load of 500 g, is monotonously increased toward the interior of the substrate and becomes constant in the range of about 50 to 100 µm from the interface.