The demand for information concerning the cataloguing process is a constant need among librarians working for the National Health System. This need is required both for the development of the traditional functions of the institutions and to face the new challenges related to the Web. With the aim of providing a version of the section devoted to cataloguing in the Procedures Manual designed for the National Medical Library, a detailed description is made of the documented procedure according to the ISO-9000 Standards. The knowledge of these techniques constitutes an urgent need for the development of the information systems in the current situation. Its validity is renewed at present due to the spreading of the use of metadata in Internet.