SUMMARY
The research objective is to analyze the major principles of IT-systems design and development and operation within the structure of the integrated architecture of electronic communications within the government authorities of Ukraine and to introduce the practical recommendations related to this issue while implementing the transition program to Unified architecture of electronic Government, that is based on the use and application of electronic services. The ways were proposed for the IT-architecture design and development within the structure of electronic communications of the government authorities on the basis of the uniform concept of the Electronic Government Integrated Architecture description. The following is considered: the basic IT-practices (models of scopes) describing IT-architecture and examples of their application at the construction of single architecture of electronic co-operation of society. The main distinctions are resulted in relation to their practical application. Development components of IT-architecture are briefly considered on the way of realization single and standardized management processes of enterprise by public institutions with the use of service-orientated approach.