DOISerbia repository has been implemented in 2005 by Department of Scientific Information in National Library of Serbia. That was one of the first developed OA repositories in Serbia. The aim of implementation of this service was improvement and promotion of scientific publishing in Serbia. System includes 66 scientific journals from Serbia with archive from 2002 till today. Every article, beside main bibliographic data is equipped with DOI number. For every journal, there are data about web address, coverage, aims and scope, publisher, editorial board, frequency, impact factor if any, and also big improvement data about journal: journal editorial policy, instruction for authors etc. On this way, it was established permanent link to full-text of every article, but also it was raised its visibility national and international. Connection between metadata of DOIs and articles is conducted via CrossRef. Since 2005 till nowadays there are over 40.000 articles in this system. The main advantage of this system is that metadata are standardized in Dublin Core and it was implemented OAI PMH protocol which opened a door for connecting and harvesting our data by big international OA repositories – TEL, Europeana and DOAJ.