Big-Data computing and services have received significant attention in recent years. The IEEE BigDataService 2019 aims to provide a forum for researchers and practitioners to exchange innovative ideas, latest research results, and practice experiences and lessons learned. Its major objectives include big-data applications in various domains such as healthcare, business and financing, education and learning, social networks and media, urban and environment, sensors and Internet of things as well as technology aspects of big data computing and services such as computing services and architecture, modeling, data mining and analytics.