2.- Objective The aim of this study was to examine the information needs of ULC users through their request journals, being able to analyse who demands the articles, the main subjects required, the information obsolescence, titles most frequently requested and their country of publication. 3.- Materials and methods Material: A total of 2517 records obtained from the software are used to manage the interlibrary loans & document supply service, GTBib-Sod v.2000, during four years, 2000–2003. Experimental design: An MS Access 2000 database was created to manage the records which combined bibliographic fields and non-bibliographic fields such as subject, year of the demand, country of publication and the type of user who ordered it. The DIALNET classification schedule was used, consisting of 13 classes and 28 subclasses, used from a total population of 77. DIALNET is a virtual library of Hispanic journals, generated by the University Library of La Rioja in 2001, and nowadays is maintained by several university libraries (one of them is the Castilla-La Mancha University Library). Sampling: Each record is classified and the country of the journal publication is added attending to “DIALNET” standards for Hispanic journals and “The Serials Directory” (Ebsco) for international journals. Procedures: Statistical analysis. Parameters determined:  Subject distribution of the journals.  Distribution of journals by country of publication.  Obsolescence of the literature demanded.  Most demanded titles distribution. The total amount of requests is 2517: 1543 from Cuenca users and 974 are supplied by ULC to other libraries. Business & Economics and Law are the classes most demanded. The 92.93% of the requests come from Social Sciences, Arts and Humanities and there is almost no demand from Science & Technology. 5.- Conclusions Economy, Law, Medicine, Literature, Art and Psychology are the most demanded disciplines. Cuenca users primarily order articles about Economy, Literature and Law, while other libraries use the system to apply for Law, Economy and Medicine journals. Spanish language and Spanish periodicals are the most demanded due to the fact that Humanities and Social Sciences are the main studies in this University campus, and use the system to do a national/local research and the results are published in national/local periodicals. Country of publication The journals have been published in 18 different countries. The Spanish demand reached 66.71%, and adding South American Countries, 67.81%. The periodicals published in English-speaking countries make up 21.61%. This implies that ULC users prefer Spanish as their language of research and secondly English. Obsolescence of the literature It has been used the “index of Price” and the “Half life” of the publications. Medicine demand is the most up-to-date and has the lowest half-life. In Economy, the ULC supplied more recent information to other libraries than what was demanded by Cuenca users. Art, Sociology and History requests correspond to articles published earlier with the lowest index of Price and a highest Half life. The literature demanded by Cuenca users is older than the demand coming from other libraries. 1.-Introduction  Research has increased lately in all areas of knowledge, and at the same time a large number of periodicals have recently been published.  Libraries have to decide which titles both satisfy their user’s informational needs and manage their subscriptions; due to this fact it is important to know their user’s typology and needs (Alvarez Ossorio, 2000).  Demand analysis of journals at the Document Supply Center could be an important tool to obtain data concerning their real use (Vázquez y Gonzalo, 1997); a study of this kind has been performed at Castilla-La Mancha University Library in Cuenca, Spain (ULC). Subject distribution (subclasses) considering the total requests and the ones demanded by Cuenca users. Economy is the subclass with the highest demand, the 65.48% are made by ULC, and just 34.52% from other libraries. Literature is mostly requested by ULC users, with 94.23% of the requests. Only 9 subclasses have been required more than 100 times (total 2117 items), reaching 84.11% of the total service demand. Six of those subclasses (1056 items, the 68.43% of the local demand) are also most used by ULC users. Only in Law and Medicine do other libraries request higher than the local demand (of ULC). A total of 1004 different titles are needed to supply the 2517 requests managed by the library service, and 734 of those are demanded by Cuenca users. 591 journal titles have been applied only once. There exists a great dispersion, but the highest demand is concentrated in a small number of journals (i.e. Economy, 20 titles, 50% of the demand). Demand of scientific articles at the University of Castilla-La Mancha main Library in Cuenca (Spain) from 2000 to María Luisa Pérez Aliende Biblioteca General de Cuenca. Universidad de Castilla-La Mancha Demand of scientific articles at the University of Castilla-La Mancha main Library in Cuenca (Spain) from 2000 to María Luisa Pérez Aliende Biblioteca General de Cuenca. Universidad de Castilla-La Mancha 4.- Results Subject Distribution The most demanded titles Only 17 titles have been demanded in more than 15 times and six are about Economy, which received 136 requests (28%), and it can be considered the nucleus of that subject.