The purpose of this study was to examine the characteristics of change in the composition of indoor spaces in Korean-style houses which have been repaired and improved extensively through the 'Bukchon Improvement Project' and are being utilized for public purposes. For this, we conducted a field survey through visiting the house sites from the 5th to the 26th of May, 2006. Conclusions drawn from this study are as follows. Bukchon Korean-style houses maintain centripetal space composition, in which the rooms surround the court. Centering on the court, the hierarchy of spaces is determined, and the hierarchy of spaces and the composition of internal layout are restructured centering on the court and the main hall without change in direction and position. The main hall is sometimes converted to a room, but it maintains an open space relation with other spaces centering on the court, and therefore, even after its use has been changed, it is still the most Korean-style space. In addition, with floor heating, the common sitting-style life is maintained continuously although the rooms have been converted and standing-style furniture is used. In this way, publicly promoted policies for Korean-style houses are allowed within the limit that the appearance is maintained and the internal spaces do not change the overall structure. However, in order to maintain the tradition of Korean-style houses and utilize them as various spaces, the following supplementations are necessary. First, the main hall and the inner court of a Koreanstyle house should be utilized actively. The court sometimes keeps individuals' privacy or expands the space by extending the view to outdoor spaces, and is sometimes used as an open space through interconnection between the inside and the outside of the house. Second, consideration should be given to vertical spaces. Horizontal expansion causes a change of floor plan. Thus, space should be secured using various cross-sectional changes, such as a kitchen and a loft over the kitchen. Third, structure should be changeable in order to adjust the size of spaces. Thus, through research on traditional windows, we need to develop changeable walls that can be installed and removed easily according to the use of spaces.