Interoperability standards play a crucial role in systems integration and information sharing in the electronic government environment. However, establishing these standards is not an easy process. Several factors, such as the number of involved agents, the environment in which the process takes place and the interrelation between the agents and the environment, not to mention the likely conflicts of interests that can rise from this interrelation, can influence it. This paper analyses the establishment of interoperability standards for electronic government. It presents the findings of a qualitative case study based on document analysis and semi-structured interviews of the Interoperability Framework specified by the Brazilian Federal Government (e-PING). The results point out some challenges to be faced, from the conception to the adoption of those standards.