Blockchain ICBC 2019 : second International Conference held as part of the Services Conference Federation SCF 2019 San Diego CA USA June 25 30 2019 proceedings This book constitutes the refereed proceedings of the Second International Conference on Blockchain ICBC 2019 held as part of the Services Conference Federation SCF 2019 in San Diego CA USA in June 2019. The 13 full papers and 2 short papers presented were carefully reviewed and selected from 29 submissions. The papers cover a wide range of topics in blockchain technologies platforms solutions and business models such as new blockchain architecture platform constructions blockchain development and blockchain services technologies as well as standards and blockchain services innovation lifecycle including enterprise modeling business consulting solution creation services orchestration services optimization services management services marketing business process integration and management