Turkish economy has been sustaining its growth process since 2001 banking crisis. In addition to this, low growth rates have been seen occasionally. On the other hand, a negative rising trend, which is seen in macroeconomic indicators such as inflation, interest rates and unemployment in the recent times, continues. In this context, foreign exchange currency rate is one of the most important indicators for all economic parts. Foreign exchange currency rates increased slowly between 2002-2013 years and increased rapidly between 2014-2016 years in Turkey. They have reached the highest level in 2017 January and have beginning to decrease after the end of 2017 January. In other words, foreign exchange currency rates shows spike increases in some periods. Mentioned condition causes uncertainty and uneasiness in one hand while affects negatively some parts using foreign exchange in the other hand. So, affecting factors must be determined in order to direct foreign exchange currency rates. This study was tried to be helpful to regulatory bodies in controlling of foreign exchange currency rates by determining which macroeconomic factors affect US Dollar and Euro in Turkey. In the study, monthly data for the period 2006:1-2017:6, 12 explanatory variables and Multivariate Adaptive Regression Splines (MARS) method was used in order to determine which macroeconomic factors affect US Dollar/TL and Euro/TL parities in Turkey. As a result of the study, it was revealed that money supply, deficit spending, foreign investment, unemployment, internal debt, exports, inflation and current deficit were the most important macroeconomic indicators for the US Dollar estimation model. In Euro estimation model, it was revealed that money supply, deficit spending, foreign investment, crude oil imports and exports were the most important macroeconomic indicators, respectively.
