An approach to develop Enterprise Integration Programs to assist enterprises in their migration path towards integration is proposed. It is called IE—GIP (Enterprise Integration—Business Processes Integrated Management, acronyms in Spanish). The topic is very important in industrial engineering nowadays because of the growing need to improve existing industrial systems and to organise such complex systems faster, better, and in a more systematic way. The contribution to the field of Enterprise Integration is mostly a methodological one. More specifically, it is based on the integration of Purdue Enterprise Reference Architecture (PERA) and Open System Architecture for Computer Integrated Manufacturing (CIMOSA) principles to propose an integration approach for industrial enterprises. Starting from existing leading proposals (CIMOSA, PERA, GERAM), a methodology has been defined and some extension to an architecture and supporting computer tools are discussed. The proposal covers the life cycle of an Enterprise Integration Program in a top-down approach. The approach is centred on the business process concept, but is based on a vision/process/people/technology view of the enterprise. The methodology divides the work into two major phases before system construction: master planning and CIM programme development. The method adapts the system life cycle of PERA but uses, whenever possible, the CIMOSA architecture with its business process approach. New CIMOSA-like constructs are introduced to be used in activities along with the methodology when necessary. To support the modelling phases of the proposal and to provide guidance to users of the methodology, computer supported tools have been developed in the course of this work.