This two volume set LNCS 9642 and LNCS 9643 constitutesthe refereed proceedings of the 21st International Conference on DatabaseSystems for Advanced Applications, DASFAA 2016, held in Dallas, TX, USA, inApril 2016.

The 61 full papers presented were carefully reviewed andselected from a total of 183 submissions. The papers cover the followingtopics: crowdsourcing, data quality, entity identification, data mining andmachine learning, recommendation, semantics computing and knowledge base,textual data, social networks, complex queries, similarity computing, graphdatabases, and miscellaneous, advanced applications.