Charging phenomena that occur during XPS and AES analysis of insulating materials are discussed, with special focus on surface potential change by X-ray or electron beam irradiation. Some typical examples of charging phenomena observed during XPS analysis are introduced together with practical methods for charge compensation and for the estimation of peak shifts by charging. As the practical methods are now under discussion in the frame of ISO activities, the content of relating ISO document (ISO 19318) is also briefly explained. Then charging phenomena observed in AES analysis of insulating materials are discussed in terms of the relation between surface charging and secondary electron emission, for which a new concept of static/dynamic secondary electron yield is explained. Practical methods for charge compensation in AES analysis are also introduced, and experimental results showing the effect of those methods are presented.