Warm Mix Asphalt (WMA) is a technology that allows significant lowering of the production and paving temperature of conventional Hot Mix Asphalt (HMA). By reducing the viscosity of bitumen and/or increasing the workability of mixture, some WMA technologies can reduce the temperature to 100oC and even lower without compromising the performance of asphalt. This promises various benefits over HMA, e.g. lowering the greenhouse gas emissions, lowering energy consumption, improved working conditions, better workability and compaction, etc. This thesis provides detailed review of these benefits and the possible specialisations for implementation of WMA. Despite the promising performance in comparison with HMA, this technology has not yet gained acceptance in asphalt industry. In order to reach widespread implementation it is necessary to prove that WMA has the same or better characteristics and long term performance as HMA. The potential problem areas and the results from research on the performance of different WMA technologies are discussed. A total of twenty two WMA products are reported including a description of the temperature reduction principle, the basic characteristics and for most of them also production technology.