The constantly increasing requirements for tool materials continuously set new challenges concerning loading capacity, resistance to damage and crack propagation as well as the characterisation of these properties, especially at elevated temperatures that arise e.g. at cutting edges when cutting metal workpieces. Essential progress in the field of tool technology and knowledge-based selection of tool materials is only possible with the coupling of FE simulation methods. Complex material data or material laws are necessary for this. The recording of the necessary mechanical properties such as tensile / compression test, low cycle fatigue, high cycle fatigue and fracture mechanical properties in the operating temperature ranges at well over 1000°C require special testing methods for these ultra-high-strength and brittle materials. The aim of this work is to present high-end mechanical testing methods for ultra-high strength tool materials that have been developed and successfully applied at Materials Center Leoben Forschung GmbH in recent years. This concerns static (tensile, compression, creep) as well as cyclic low cycle fatigue testing under uniaxial load from room temperasture to over 1000°C e.g. of high speed steels, hardmetals or refractory metals. Further methods concern fracture mechanics characterization such as fracture toughness or cyclic crack growth. These investigation methods are coupled with high-end microstructural investigation methods, such as high resolution scanning electron microscopy with focused ion beam including high resolution / high-temperature electron backscatter diffraction. The work gives an overview of these modern investigation methods on the basis of various investigation examples on a variation of different tool materials with concrete investigation examples in a strength range from 3000 MPa to 8000 MPa and in a temperature range up to 1400°C.