Lack of land for a large project in Taiwan is not only a problem for housing but also for office and retailing development. In order to satisfy the requirements for eminent office spaces and high-end shops to be located in a prime location, developers often engage in the assembly of a number of contiguous sites. In spite of numerous studies into land assembly for housing development, very little research has been undertaken to examine office or retailing development. Studies on land assembly for housing development have highlighted the problem of land fragmentation and its effects on later development, including development pace and pattern. We set out in this study to examine how land is assembled for office and retailing development in one of the major commercial areas of Taipei. The study area is Sinyi shopping area where both Taipei 101 Building and Taipei City Hall are located.Our expectation is that small sites need to be assembled into a larger one before those large-scale projects are possible. With the help of detailed cadastral and ownership records, we measure the degree of land fragmentation over time. We hope through this study to understand how commercial sites are assembled and how the degree of land fragmentation changes in response to the market conditions and development pressure. Also, we hope to understand why after over 30 years, some sites have now developed into high-end offices and department stores, but some fairly expensive sites next to them are still left idle. All these findings could significantly improve our understanding of how Taipei grows and if land at prime locations is in an efficient use.