Search examiners at DG 1 of the EPO are largely involved in documentation activities. They classify EP- and PCT-applications for publication using the International Patent Classification (IPC), and they classify new patent documents and non-patent literature for addition to the systematic search documentation. They use the European Classification (ECLA), an internal classification tool developed on the basis of the IPC but with further subdivisions and better adaptation to the different technical fields. For maintaining or improving the quality of the search documentation, the examiners continuously reorganise the internal classification system.In order to overcome the limitations of a classification system, secondary systems are in use or under development. A successful example of such systems is the ICO system. This system offers light indexing schemes for the identification of additional information contained in patent documents. The indexing codes are only available online; they are not used when filing actual patent documents.