Describes the Unired Union Catalogue Project. Unired, economic and social sciences information network, is a co-operative system established in Buenos Aires in 1989 as a mechanism to find, promote and exchange bibliographic information. The Unired social and economic sciences database provides access to more than one million bibliographic references to documents, including data of the depositary library. The Unired Union Catalogue is formed by 88 libraries of government, private and international institutions. The URL of the database is http://cib.cponline.org.ar/unired.htm. The 92% of the libraries uses Unesco ' s CDS/ISIS (MicroISIS). The 65% uses CEPAL bibliographic format and 7% uses MARC format. Unired uses the CEPAL format as an information interchange format. All databases were transformed to CEPAL format, and the quality control was done with BIREMEs CISIS. The online catalogue was builded with BIREMEs WWWISIS search engine. The session will show a table with the evolution of the database, starting with the first version of 1995 (137,186 records of 29 libraries), until the last update in 2004 (1,321,062 records of 88 libraries). The poster session will offer details about database updating work and quality control processes, also new features of the search interface, technical and human resources and participating institutions.