Source-based and detector-based radiometry has been realized in the X-ray range during the last few years by using synchrotron radiation.Electron storage rings are operated as primary source standards and cryogenic Electric Substitution Radiometers(ESRs)as primary detector standards.As ESRs require intense monochromatic radiation,synchrotron radiation is also necessary for this approach.Energy-dispersive detectors as well as silicon photodiodes have been calibrated with relative uncertainties of the detection efficiency or responsivity down to about 1%.The results are compared to model calculations.