Field‐electron microscopy and low‐energy‐electron diffraction can be used in a complementary manner. A method of making such a direct combination on a single specimen is described and applied to a study of the problem of carbon contamination of tungsten surfaces. It is shown that, within the sensitivity of the apparatus used, carbon may be present and remain undetected by the display mode of LEED on a (nonperfect) (011)‐oriented W LEED specimen.