[en] The metal dispersion in 0.5 % Pd/Al₂O₃, 0.5 % Pt/Al₂O₃ and 1.5 % Pt/Al₂O₃ catalysts was investigated by small angle X-ray scattering. Using a Kratky camera the difference scattering curves catalyst-carrier were evaluated. The assumption was made that the scattering centres are globular and that there is no interparticular scattering. From the Guinier approximation the Guinier radii Rsub(G) of the metal particles were determined. With the Pd catalyst always positive difference scattering curves were found, whereas negative values were found with the Pt catalysts at a scattering angle greater than 0.022 rad. Therefore only for the sample with 0.5 % Pd the Porod invariant Q tilde and the Porod radius Rsub(P) could be determined. From Rsub(G) and Rsub(P) the parameters of a two- and of a one-parametric distribution were calculated. The results are in good agreement with data from wide angle X-ray diffraction measurements. (author)