This paper analyses the total final energy consumption (TFC) for industry, transport and agriculture sectors in Algeria during the decade of 1998-2008, the total final energy by activity sector and fuel type, the total energy intensity evolution and the impact of energy consumption in Algeria on the environment. The total final energy consumption (TFC) in 2007 reached 20 million TOE, for 34.4 million inhabitants occupying 2 393 367 square km of land, and with a Gross Domestic Product (GDP) equal to 9 389.70 million DA (Algerian Dinars). The consumption per capita in Algeria is 1 058.0 kilograms of oil equivalent (kgOE) per person, while in Morocco, which has nearly the same number of inhabitants it is 458 (kgOE) and in Tunisia the figure is 843 (kgOE). The total gas emission is equal to 46 million tonnes of CO2 with an average of 3 TECO2/TOE. The GDP is equal to 3 232.2 million DA. Detailed information on different industrial sectors, different transport means sector, as well as the agriculture sector have been presented and discussed in the paper. The final energy intensity in Algeria has stabilized at around $ 0.53 TOE/1000 between the years 2000 and 2003. It has been improved by 2% between 2003 and 2007, exceeding 0.41 TOE /1000, which indicates an elasticity of about 1.23 .This performance is due to an optimization of the rate of capacity utilization (TUC) of the production system. The energy intensity reflects the degree of dependence of an economy with respect to the energy factor. The higher the energy intensity, the more vulnerable the economy is to the fluctuations in energy cost. Energy intensity is also a relevant indicator according to the obligations taken in the Kyoto Protocol. Emissions of greenhouse gases due to the final energy consumption reached 46 million TCO2.