The Agricultural Research Service (ARS) of the U.S. Department of Agriculture uses standardized designs for its research greenhouses in order to (1) provide a data base on and a consistent analytical approach to greenhouse design; (2) tim# design variability and therefore reduce costs and time associated with greenhouse design; (3) increase control of the quality of the final product; and (4) provide a built environment that both responds to current research needs and can accommodate changes required by future research objectives The designs are developed by assembling standard systems and components. An expert system was developed to assist the ARS scientists in formulating building programs that are appropriate for particular research, economic, and climatic conditions encountered at ARS centers across the U.S. The expert system accesses a knowledge base of architecture, engineering, and heuristic rules and uses a multiple-attribute analytical technique to weigh competing objectives in the decision making process. First, the expert system translates the research needs of the scientists into functional requirements for the greenhouse. Based on those functional requirements, recommendations are made for the use of specific greenhouse systems, subsystems, and components and for implementation of specific operation strategies. This paper describes the development of the expert system and demonstrates an application.