This paper presents a conceptual design of a Performance Benchmarking System (PBS)for buildings called Buildings PBS, which aims to create an online knowledge-basedsystem for the life-cycle performance assessment of buildings. The research presented inthis paper is based on the concern that the performances of buildings are vital for bothwell-being and energy saving throughout their life-cycle. In order to achieve theBuildings PBS, this paper describes several research essentials such as the methodology,the deliverables, and the demonstration.