Abstract: Special libraries are not independent institutions. They belong to the group of libraries that are within other organizations for which librarianship is not their primary activity. Unequal degrees of development of special libraries represent an important characteristic of their actual state and presents the main difficulty in making precise analysis. Given the huge differences in the development of the libraries, only the basic statistics for the last five years are given in this Work. The starting point for the analysis of the general state of special libraries is their precise categorization, in order to analyze their needs and to improved their work in conditions comparable with similar libraries. An explained Categorization of Special Libraries is given in this Work, in relation to the type of organizations to which they belong.