This book constitutes the refereed proceedings of the 20th International Conference on Business Information Systems, BIS 2017, held in Pozna?, Poland, in June 2017. Big Data Analytics helps to understand and enhance enterprises by linking many fields of information technology and business. This years conference theme was: Big Data Analytics for Business and Public [url] 24 full papers presented in this volume were carefully reviewed and selected from 72 submissions. They were organized in topical sections named: big and smart data; business and enterprise modeling; ICT project management; process management; smart infrastructure; and applications.