In Turkey, as a developing country, environmental impact assessment (EIA) Is a critical key for environmental protection. EIA is not regulated in Turkey by means of law, but through a decree put into force on the basis of the relevant provision of the Environmental Law. The Environmental Impact Assessment (EIA) System, which embodies the "prevention principle" of the environmental law, is an important tool for environmental protection. This tool has a private importance for Turkey since it is a developing country, and it entered the Turkish law in 1983 with the Environmental Law. Besides, the EIA Regulation, which shows the application principles, became effective in 1993. Because Turkey is a candidate for European Union (EU), the EIA Regulation has been changed due to the EU compliance procedure, and its latest version became valid in 2014. This study aims to emphasize The EIA system in Turkey to supervise the efficiency of this procedure and point the success level.