Belgium has an ambitious climate change target of -7.5% for all six geenhouse gases mentioned in the Kyoto Protocol (CO2, CH4, N2O, HFCs, PFCs, SF6) to reach by 2008-2012. The target is ambitious given the current rising trends in greenhouse gas emissions in the country, though it is average compared to a global EU target of -8% for all greenhouse gases. The remaining 10 years up to 2012, however, leave little margin on action and an ambitious reduction of energy demand is necessary in combination with supply efficiency measures (both on fossil supply and renewables) and measures for non-CO2 greenhouse gases. In this context, the present study was commissioned by the Ministry for Economic Affairs with the aim to investigate in detail the role that energy efficiency at the demand side had been playing in Belgium energy policy so far and what elements of energy efficiency could be promoted to increase its role in the future, taking into account the particular federal structure of the Belgium state. Energy efficiency is not an isolated element of energy policy but embedded in a general context of energy policy.