In this study, an intelligent energy-efficient outdoor lighting control system was developed that could be used in green buildings as well as intelligent building functions, and contribute to the reduction of carbon dioxide emissions by using more conservation of electric energy and daylight more efficiently. The intelligent energy-efficient lighting control system was based on expert system is one of the artificial intelligence techniques and has four functions running in real-time. The first function is controlling and monitoring of the lamp groups. The other functions are fault diagnosis in lambs and power lines connected to the lamp groups and the load estimation of lamp groups. The expert system was written in two separate computer and microcontroller based environments by using knowledge-based rules.