Because of the simplicity and intelligibility, ratio of GDP to energy consumption is one of the most popular indicators to measure energy efficiency. However, traditional energy efficiency indicator considers energy only as a single input. This indicator may easily overestimate the real change in energy productivity when energy is substituted for other inputs. Also, traditional indicator disregards the technology level of energy use. In other words, the traditional indicator assumes the technology is always constant from year to year while due to the technical progress, productivity is also improved. The aim of this paper is to introduce a Total Factor Energy Productivity Index which has no mentioned defects of traditional index. More, this index is used to compute energy productivity for 20 developing countries. Findings show that the majority of developing countries experienced negative energy productivity growth. The TFEPI Index shows that Syria has the highest energy productivity growth and Qatar and Yemen are located in subsequent positions and Iraq, Oman and Bangladesh have the lowest TFEPI growth. Iran is also placed in 13th position by an average growth of -0.015. Furthermore productivity decomposition to total-factor energy efficiency and total-factor energy technical changes indicates negative technical change is the main reason for being negative of TFEPI. Recent plan subsidies and energy price reform has increased energy efficiency in Iran. Hence, in order to increase energy efficiency, it should be considered the promotion of energy technology.