In this article, analysis of the sectoral energy consumption values is presented over the years 1980-2005 for Turkey. As a basis for the article, four main sectors (agriculture, service, transportation and industry) are considered. Change in sectoral energy consumption is analyzed using the decomposition method for three factors (output effect, energy intensity effect, structural effect) and computing all various combinations of these effects. Taking into account final energy consumption values and sectoral value added, and dividing the 25 years of the study period into 5-year periods, an in-depth analysis is carried out to see in which period the used factors are more effective. Results of the analysis offer that the most important factor affecting energy consumption is found to be the output effect. However, the energy intensity effect provides a negative contribution.