pISSN 1598-2033 eISSN 2233-5706 Journal of the Korea Institute of Building Construction, Vol. 12, No. 5 http://dx.doi.org/10.5345/JKIBC.2012.12.5.528 www.jkibc.org 528 As in recent years construction projects have become larger, more specialized and more advanced. the construction industry is making efforts to diversify functions and types while pursuing quantitative and qualitative growth. A construction project consists of a series of processes with diverse characteristics, from planning to design, construction, maintenance and waste disposal[1]. The processes have different cost breakdown structures(CBS) by phase, which poses a problem in calculating construction work cost in a reasonable manner. For this reason, designers and engineers spend a lot of time and expense estimating and calculating building construction cost of a construction project by phase [2]. To make a reasonable calculation of construction cost, both initial construction cost and Life Cycle Cost (LCC) should be considered. However, the CBS used in bills of quantities for construction work for LCC estimation is classified by work type, while for maintenance cost estimation the elemental cost breakdown structure is employed. which means that an error may occur in the course of integrating the two CBS. In addition, a different replacement cycle for each element should be applied to estimate maintenance cost, but the construction cost items have not yet been standardized, and it is difficult to accurately reflect costs at an early phase of a construction project[3]. To address this problem, a CBS should be established for easy LCC estimation by phase of a construction project. Hence, this study aims to develop CBS for LCC estimation of a structure using the Delphi analysis. If a CBS is developed. the construction work cost can be