Radiometry based on black bodies remains one of the fundamental fields of radiometry. Black bodies are widely used as standard sources in radiometry of noncoherent optical radiation from the ultraviolet to the far-infrared spectral regions. Outstanding progress in radiometry has been made in the last decade due to development of high-precision cryogenic radiometers, which have made it possible to decrease the measurement uncertainty to 0,01%. New technology and optical physics call for significant improvement in the accuracy of black-body-based radiometry and the practical realization of spectral radiance and irradiance scales having an accuracy of 0,1%. However, the accuracy of black-body-based radiometry is now limited by the accuracy of thermodynamic temperature measurements of a radiating cavity. For example, the uncertainty of spectral radiance and spectral irradiance scales is from 0,5% to 1% in the UV due to uncertainties in pyrometric measurements. The required uncertainty of modern black-body-based radiometry is about 0,1%. This can be achieved by using the latest advances in the field of high-precision radiometric instrumentation, such as absolute radiometers, large-area high-temperature black bodies and synchrotrons.