We describe a building-integrated photovoltaic system, believed to be the first of its kind in Korea. The PV cells are mounted on the south facade and on the roof of the Samsung Institute of Engineering and Construction Technology (SIECT), in the Gihung area. Special care was taken in the building design to have the PV modules shade the building in the summer, so as to reduce cooling loads, while at the same time allowing solar energy to enter the building during the heating season, and also to provide daylight. The paper gives an account of the integration of the system into the building, an analysis of the system performance, and an evaluation of the system efficiency and the power output, taking into account the weather conditions. As pan of certain design compromises that took into account aesthetic, safety, and cost considerations, non-optimal tilt angles and occasional shading of the PV modules made the PV system efficiency lower than the peak rating of the cells. Nonetheless, the PV share of the SIECT building＇s electrical demand reaches 10% on a typical July day.