This volume contains papers presented during the science trace at the 4th International Conference of Business Information Systems, BIS 2000, held in Poznan, Poland, 12-13 April 2000, which discussed the development, implementation, applications and improvement of computer systems for business processes. The papers deal with practical, industry experiences and validated prototype implementations, and cover areas such as integration of information systems, electronic transactions and banking, virtual organisations, network technologies, business information systems modelling and analysis.