Proliferation of IT applications and developments lead to many useful yet diverse information systems being used in an organization. Users of information system have been satisfied with useful functions and prompt outputs, however they have become realized the problem of incompatibility of diverse systems and asked for more compatible systems in which more data and software can be shared among users. Information technology architecture (ITA) is suggested as one way of avoiding such problem by many researchers. This paper ananlyzes and introduces the ITA approach used primarily in US governments and in many other organizations. In Korea, many researchers view ITA as a technical concept that deal with interperability and standards. However, ITA is more managerial oriented concept than technical, because it allows us to achieve managerial objective, for example alignment of IT to strategic objectives, with ease and more confidence. This paper proposes the necessity of ITA in IT management and clarifies the relationships of managerial focus with technical focus of ITA.