This study investigates the relationships among electricity consumption, real economic activity, real price of electricity and the UEDT (underlying energy demand trend) at the aggregate and sectoral levels, namely, for the residential, commercial, industrial, and agricultural sectors. To achieve this goal, an electricity demand function for Pakistan is estimated by applying the structural time series technique to annual data for the period from 1972 to 2012. In addition to identifying the size and significance of the price and income elasticities, this technique also uncovers UEDT for the whole economy as well as for sub-sectors. The results suggest that the nature of the trend is not linear and deterministic but stochastic in form. The UEDT for the electricity usage of the commercial, agricultural and residential sectors shows an upward slope. This upward slope of the UEDT suggests that either energy efficient equipment has not been introduced in these sectors or any energy efficiency improvements due to technical progress is outweighed by other exogenous factors. (C) 2013 Elsevier Ltd. All rights reserved.