Site Layout generally involves planning and locating the temporary facilities that are needed to support building operations duting the construction phase. Effective site layout can increase the productivity of projects resulting in a reduction in project time and cost. Poor site layout, on the other hand, can be a major obstacle to the project success. These research studies the problems associated with the temporary facility layout of building construction projects in Thailand. A swvey was conducted to collect the information fkom nine construction projects regarding twenty temporary facilities normally found in most construction sites. The information was obtained by distributing a set of questionnaires to those responsible for the task as well as interview with five experts. The results indicate the average expenditures of temporary facilities is 0.98 % of the project cost. The top four most fkequently mentioned problems were: 1) inadequate space, 2) budget limitations, 3) law and regulations, and 4) lack of cboperations fkm the working level personnel respectively. Factors that are concerned in temporary facility planning are: I) time, 2) quality,3) safety, 4) cooperation, 5) Environment and 6) cost respectively.