Professional Graduate School of Business(PGBS) System was introduced by the Ministry of Education and Human Resources in 1988 to raise professional business leaders. This paper analyzes the operations of the initially approved PGBS of Sungkyunwan University and others. PGBS system tried unsuccessfully to provide the institutional framework for full-time MBA programs because of its stringent institutional requirement of abolishment of the Graduate Business School for Evening MBA at the same university. Problems of old PGBS systems and their potential solutions are discussed. It is also shown how New PGBS system since 2006 deals with the old problems.