AbstractExtensive studies of the components and distribution which govern background x‐ray intensity in the short wavelength region of wavelength‐dispersive spectrometry have been made. The theoretical calculations account for the contribution of coherent scattering (including anomalous dispersion factors), Compton scattering and absorption effects. For the precise comparison between the calculated and experimentally measured intensities, coherent and Compton scattered intensities of Rh Kα and Rh Kβ emitted from a rhodium‐target x‐ray tube were investigated with respect to different kinds of specimens. From the differences in the calculated and measured intensities, the intensity tailing of the large peak of the major components was found to be the Compton scattering of fluorescent x‐rays. A theoretical expression for calculating the magnitude of the background x‐ray intensity using an appropriately selected standard sample is described. The application of Co Kα x‐rays interferred by Fe Kβ x‐rays and the small intensity change in background x‐rays for the trace element analysis of steel