Since the 1990s, discussions regarding green libraries started in the U.S.A, in the name of `library and the environment`, `Green librarians`, `constructing of environmental sources`, `noise and library`, `building libraries as an environmental alternative` and etc. Currently, green libraries certified by an evaluation system are more than 50. This study proposes a direction to build a green library. The study analyzes national and international green libraries certified by the evaluation system. The cases are analyzed based on the six evaluation factors in the LEED certification system; Sustainable Site, Water Efficiency, Energy and Atmosphere, Material and Resources, Indoor Environmental Quality, Innovation and Design Process. Since the evaluation system focuses mainly on the architectural aspects, there was a need of expanding the concept of eco-friendly in this research. The newly expanded eco-friendly concept includes services, content, and supplies of libraries.