This volume presents papers from the Ninth International Baltic Conference on Databases and Information Systems (Baltic DB & IS 2010) which took place in Riga, Latvia, in July 2010. Since this successful biennial series began in 1994, the Baltic DB & IS conferences have become an international forum of high scientific criteria for academics and practitioners in the field of databases and advanced information systems (IS), as well as for the related areas of semantic technologies, ontologies and advanced software engineering technologies for information systems development and security. The interna.