e-Government can be defined as Internet applications for public administration processes and decisión making on local, regional, national as well as cross-national level. Therefore, the strong necessity to ensure vertical and horizontal interoperation of administrative units is arrived. The main goal of the paper is to reveal how interoperability is built into the public administration engineering process. The paper covers explanations how interoperability is important for e-governmental processes covering documents flows and what activities have been realized with EU agencies to ensure interoperability development. The first part of the paper comprises explanation of e-Government document engineering and administrative process development. The second part covers consideration on interoperability for e-Business and public administration. The third part includes analysis of what standardization is demanded for interoperability of e-Government agencies and how different countries’ governments are prepared to ensure such interoperability in public administration in the light of documents, institutional norms and open standards.