AISI P20 is generally labeled as a mold steels. It is a pre-hardened high tensile nitriding tool steel which possesses high hardness. This makes it difficult to be machined due to the high tool wear rate compared with other workpiece materials. Hence, the tool life will be shortened and reach the critical failure faster than usual. This work reports an experimental study on the effects of cutting conditions on tool life and possible wear mechanisms when face miling of AISI P20 using carbide tools.