This article analyzes the institutionalization of the presidential secretariat(PS) in Korea from 1948 to the present. The PS was poorly institutionalizedfrom the 1940s to the 1960s, but it has rapidly expanded and differentiated since1968. Although presidents since the democratic transition in 1987 have effectivelycontrolled any expansion of the number of senior secretaries, the PS`s total sizehas continued to increase, especially during the latter part of each administration.It has undergone institutional experiments responding to changing environmentalchallenges. The PS has become a core institution for executive and economicpolicy functions since 1968, at which time its expenditures began to increasesteadily, enhancing its autonomy. And, socio-cultural, welfare, and educationaffairs have been a particular focus of institutionalization since 1987. The PS hasbeen highly professionalized, staffed mainly with public servants and expertsrather than politicians. This has caused it to be oriented toward the long term andconsistency rather than the short term and flexibility.