In recent years, “Big Data” has become a new ubiquitous term. Big Data is transforming science, engineering, medicine, healthcare, finance, business, and ultimately society itself. The IEEE Big Data has established itself as the top tier research conference in Big Data. The first conference IEEE Big Data 2013 ( http://cci.drexel.edu/bigdata/bigdata2013/, regular paper acceptance rate: 17.0%) was held in Santa Clara, CA from Oct 6-9, 2013 with more than 400 registered participants from 40 countries. The IEEE Big Data 2014 ( http://cci.drexel.edu/bigdata/bigdata2014/index.htm, regular paper acceptance rate: 18.50%) was held in Washington DC, Oct 27-30, 2014 with more than 600 registered participants from 45 countries. The 2015 IEEE International Conference on Big Data (IEEE BigData 2015) will continue the success of the previous IEEE BigData conferences. It will provide a leading forum for disseminating the latest research in Big Data Research, Development, and Applications.