Usage of ethanol as a fuel has been known for hundreds of years. However, recently usage of ethanol and its blends as a road transport fuel has increased and interest in its use is growing. There are a lot of pros and cons connected with using ethanol, which are described in this paper. This paper reviews current knowledge on using ethanol in spark ignition engines. The fuel is described in the context of future opportunities. A significant part of the paper is dedicated to the analysis of ethanol and its blends’ impact on regulated and unregulated exhaust emissions, including laboratory results obtained by BOSMAL from chassis dynamometer testing of European vehicles.