The vicinal surfaces of silicon are prepared with very regular step structures. As a special feature some surfaces show regular structures with triple steps. The structure of the triple step, however, cannot be determined with STM due to the size of the tip. Therefore a kinematic low energy electron diffraction analysis has been made using the variation of the spot positions and intensities of a high number of diffraction spots with energy. It is shown, that the triple steps at the Si(5 5 7) surface have the orientation of the (1 13) face. This information is needed for description of the growth of other materials on top of the vicinal surface. 2002 Elsevier Science B.V. All rights reserved.