This paper refers to the opportunities to utilize some econometric models in the macroeconomic studies. In this respect, authors concentrate on the possibility to use the simple linear regression model in analysing the evolution and correlation between the Gross Domestic Product and some macroeconomic aggregates. Under these circumstances, there are considered this macroeconomic indicator of outcomes as being the dependent variable, whose variation is significantly determined by the evolutions recorded by the parameters of the economic and social development of the country. The evolution of the Gross Domestic Product is supposed to be mainly influenced by the dynamics of the investments. However, in Romania, the current economic context is characterized by relatively low values of investments, at all stages, as the internal investments are very small as value, the foreign direct investments keep also low because, mainly, of the legal framework, and the absorption of European funds is not satisfactory. Therefore, at this stage, we focused on the investments and the final consumption as factors of GDP evolution. The value of the investments and the final consumption made at the level of Romania's economy has been defined as independent variables. It is extremely important to define the role played by the macroeconomic indicators as to increase/decrease the value of the Gross Domestic Product, generally speaking, and particularly in the case of Romania.