Abstract: Modular extrusion die tools for extruding an extrudable material into an extruded article. In at least some embodiments, an extrusion die tool comprises a base, a sizing plate, a mandrel, and a die holder. When the sizing plate and mandrel are removably inserted into the base, and the base is removably inserted into the die holder, a billet of extrudable material may be injected under high pressure into the die tool. As it exits the die tool, the material is extruded into a desired shape. Because of the extreme forces to which the extrusion die tools are repeatedly subjected, some portions of the die tools can wear out relatively rapidly. Other portions, however, wear at a much slower pace. Consequently, certain portions of the die tool may need to be replaced more frequently than other portions. Because the extrusion die tools of the present invention are modular, the highly-worn portions of a die tool may be replaced without replacing the entire tool.