Energy intensity index represents the amount of energy consumed by each of the energy carriers per unit (production or added value).  Considering the role and significance of this index in the economies of the countries, this research covers factors affecting energy intensity in the OECD countries during 2001-2014 using data panel econometrics and generalizes method of moments.        During the years under study in this research, energy intensity of the previous period, GDP, foreign currency rate, HDI and Internet Users of the countries have been of the utmost significant factors affecting the energy intensity of the OECD countries. Meanwhile the energy price, as a factor, has had impact on the energy demand and consequently energy intensity. The results indicate that there is a meaningful and negative correlation between energy intensity and energy price, GDP, foreign currency rate and internet users while there is a meaningful and positive correlation between energy intensity and HDI and energy intensity of the previous period.