The objectives of this work can be divided into theoretical and empirical. The theoretical goal of the investigation is to determine the theoretical bases of relations determinants of credit ratings and the credit ratings of EU countries. Determining the theoretical background is essential in order to interpret the results of empirical research and provide guidance for further research. The main objective of this study was to prove that the main determinants of the credit ratings of EU countries are: GDP growth, annual inflation, fiscal balance, public debt, unemployment and EMU membership. The results showed that the latter variables are significant for sovereign credit rating of the observed countries. Some have positive and some negative impact on the rating. In most models which appear GDP growth and membership in the EMU had a statistically significant positive impact on the credit rating. Annual inflation, public debt and unemployment rates have a negative impact on the credit rating, while the fiscal balance of 7 models which shows statistically significant, in 5 models has a negative impact on the credit rating. In terms of development, more developed countries have a higher credit rating. This is due to the observed determinants which have very good results, and accordingly these and appropriate evaluation. While on the other less developed countries that do not have or do not have all that good indicators, and they accordingly have a lower rating.