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This paper tries to model the electricity demand in Iran’s industrial sector which captures economic factors and also non-economic exogenous factors. The structural time series model (STSM) approach is employed which allows using economic theory and time series flexibility. In this approach the role of UEDT (Underlying Energy Demand Trend) including technological improvement and structural changes is modeled, therefore the income and price elasticity are estimated more accurately. The results show that the UEDT has the stochastic nature. And UEDT has a great impact on industrial energy demand during 1975-2012. So, the electricity has not been used efficiently in this sector. In the short run the estimation of the income and price elasticity are 0.42 and 0.11 respectively. The value of the cross-price elasticity of electricity demand is estimated about 0.06. It shows that natural gas substitute electricity in industrial sector, however it is small.