Environmental Impact Assessment (EIA) studies have taken place in developed and developing countries both as legally and practically, while it reached legal status through the 10th article of the Environment Law entered in force in 1983 in our country. After the Ministry of Environment was established, it was carried into practice as legislation on February 07, 1993. The legislation was changed in 23 June 1997 with the aims of solving the problems raised in practice and providing effective and efficient implementation. Later on, within the scope of harmonization works with the European Union (EU) Legislation and in line with the EU EIA Directive, the EIA Regulation was revised again in 2002 and 2003 and entered into force after promulgated in the Official Gazette in 16 December 2003 with the number of 25318. Following the legislation published in 2003, the regulation was rectified in 2008 and 2013 and finally has been revised in 2014 to take its current form as it is today. In this study, the changes in the EIA regulation-that was completely amended total of 7 times in the 23 years period since 1993- are discussed. In addition, the changes in the process of preparing the EIA report under changing and developing conditions in Turkey were examined in detail as of today.