Warm Mix Asphalt (WMA) technologies allow significant lowering of the production and paving temperature of the conventional Hot Mix Asphalt (HMA), which promise various benefits, e.g. lowering the greenhouse gas emissions, reduction of energy consumption, improved working conditions, better workability and compaction, etc. However, in order to reach widespread implementation of WMA, it is necessary to prove that it has the same or better mechanical characteristics and long-term performance as HMA. This article presents a laboratory study that has been conducted to evaluate two different WMA technologies – chemical (using Rediset WMX®) and organic (using Sasobit®). The aim of the research is to investigate the changes in bitumen consistency after the modification with WMA additives, to determine the physically-mechanical properties of asphalt after reduction of compaction temperature and to compare the qualities of WMA with those of conventional HMA. The properties of two types of bitumen after modification with two different dosages of each WMA additive have been tested by traditional empirical test methods and with the Dynamic Shear Rheometer for a wide temperature range. The results suggest that the binder, containing Sasobit®, at in-service temperatures and short loading times that are typical for traffic, has improved elasticity and lower viscosity if compared to pure bitumen. Rediset WMX®, however, had only minor effect on the binder properties suggesting that the additive changes the interaction between bitumen and the aggregates rather than bitumen itself and therefore should be evaluated in context with the designed asphalt mixture. Asphalt testing has been performed for Stone Mastic Asphalt mixture. At first, the necessary changes in testing conditions were determined by means of asphalt stiffness – the results suggested that for adequate comparison with reference HMA, two hour asphalt aging is essential before preparing test specimens. The properties of asphalt were determined for specimens that were prepared at four different compaction temperatures by means of two compaction methods – Marshall hammer and gyratory compactor. The test results showed poor correlation between the compaction methods in most of the tests. However, in general the results of compactibility and density suggest that modifying the bitumen with WMA additives allows reducing the compaction temperature by at least 30°C and still reaching similar compaction level as for HMA. The properties of stiffness and resistance to permanent deformations also show that it is possible to reduce the compaction temperature of 155°C for HMA to 125°C for both WMA products with maintaining similar mechanical characteristics as for HMA.