The impact of ICT on energy consumption is one of the most important and multifaceted topics. Expansion the ICT can reduce energy consumption by increasing efficiency while the emergence of new products and services in this regard will lead to additional demand for energy. Accordingly this study examined the non-linear effect of ICT on energy consumption in Iran over the period 1974-2012. For this purpose, used the energy consumption per capita and the ratio of ICT capital stock in the communications sector to GDP (as an indicator ICT) variables in the form of a smooth transition regression (STR) regime change as one of the outstanding models. The estimated STR model supports a nonlinear threshold behavior in the relationship between ICT index and energy consumption per capita in in a two regime structures with a threshold level of about 9.62 percent. So that ICT index in the first regime had positive impact energy consumption per capita, while in the second regime this effect is negative. . So we can expect that by increasing the capital stock of ICT in the communications sector to GDP ratio than threshold level, seen a decline in energy consumption per capita in the country.