The combination of scanning electron microscopy (SEM) and scanning optical microscopy (SOM), including a computer‐controlled signal detection system, is promising in the study of a variety of materials, especially such alkaline‐earth oxides with a rock salt structure, such as MgO. Among the SEM modes of this technique used to investigate deformed zones in indented MgO single crystals are: secondary electrons (SE), cathodoluminescence (CL) (total, pointal, color), electron beam‐induced current (EBIC), electron beam‐induced voltage (EBIV), as well as both polarized and transmitted light modes in SOM. The present experiments were designed to clarify the correlation between the optical, luminescent, electrical, and plastic properties of deformed MgO. An attempt has been made to explain the results in terms of dislocations created during deformation.