The two-volume set LNCS 5990 and LNCS 5991 constitutes the refereed proceedings of the Second International Conference on Intelligent Information and Database Systems, ACIIDS 2010, held in Hue City, Vietnam, in March 2010. The 94 revised papers presented presented together with 2 keynote lectures were carefully reviewed and selected from 330 initial submissions. The papers are thematically divided into two volumes; the first includes all the contributions mainly related with intelligent database systems, data warehouses and data mining, intelligent information retrieval, technologies for intelligent information systems, and applications of intelligent systems. The second volume collects the papers related with Web-based systems for data management, autonomous systems, collaborative systems, tools and applications, multiple model approach to machine learning, and modeling and optimization techniques in information systems, database systems and industrial systems.