These proceedings contain 25 contributed papers presented at the 13th East- EuropeanConferenceAdvances on Databases and InformationSystems (ADBIS 2009) held September 7-10, 2009, in Riga, Latvia. The Call for Papers attracted 93 submissions from 28 countries. In a rigorous reviewing process the inter- tional Program Committee of 64 members from 29 countries selected these 25 contributions for publication in this volume; in addition, there is the abstract of an invited talk by Matthias Brantner. Furthermore, 18 additional contributions were selected for short presentations and have been...