This work deals with the development of methodical subject analysis and indexing, based on theoretical findings, for the marine scientific documents in the IZWOlibrary. The developped method is tested by analysing some example documents. This shows that the results of the analytical method are sound and useful for subject indexing. Putting this method to practice at the library depends however very much upon the resources granted to this library. This is discussed through analysis of the basic tools needed for good subject indexing. Nevertheless, the resulting method seems to be a good starting point for further practical elaboration.