This volume constitutes the proceedings of the 13th International Conference on the Entity-Relationship Approach, ER '94, held in Manchester, UK in December 1994. The ER '94 book is devoted to business modelling and re-engineering and provides a balanced view between research and practical experience. The 34 full revised papers presented are organized in sections on business process modelling, enterprise modelling, systems evolution, modelling integrity constraints, object-oriented databases, active databases, CASE, reverse engineering, information system modelling, schema coordination, and re-engineering.