This book contains substantially extended and revised versions of the best papers from the 13th International Conference on Enterprise Information Systems (ICEIS 2011), held in Beijing, China, June 8-11, 2011.  The 27 papers included (plus one invited paper) in this volume were carefully reviewed and selected from 57 full papers presented at the conference (out of 402 submissions). They reflect state-of-the-art research that is often driven by real-world applications, thus successfully relating the academic with the industrial community. The topics covered are: databases and information systems integration, artificial intelligence and decision support systems, information systems analysis and specification, software agents and Internet computing, and human-computer interaction.