This European Standard provides a generic description of the maintenance process. It applies to all maintenance systems and all organisations. Therefore, it has been established without a particular organization in mind and does not aim to propose one. The purpose of the breakdown into processes and the representation of their inter-relationships1 is to help maintenance personnel, and particularly management at different levels, to: clearly identify the actions to be taken in order to meet the overall objectives set by Management in terms of maintenance; delegate responsibilities that ensure the realization of the actions with the required performance levels; for each process, clearly determine: the necessary inputs and their origin; the required results and their intended uses; monitor and quantitatively assess the performance obtained at various levels of the breakdown into processes. improve the collection and the distribution of data. This description should be adapted based on the type of organization chosen to perform the maintenance, the complexity of the systems maintained and the scope of the external contracted services. This standard does not cover software maintenance itself, but applies to items containing software.