Being the cleanest mine fuel due to the release of low exhaust emissions into the atmosphere, natural gas has been utilised by many fields of transport. A rapidly growing world market of liquefied natural gas (LNG) fuel has enabled to implement this fuel in urban transport. This article concentrates on presenting an alternative solution for the use of LNG fuel in urban buses to reduce exhaust emission using the example of Szczecin. On the basis of a significantly growing segment of the engines for the gas driven market, the article also shows the possible costs arising from the use of LNG fuel in urban buses of Szczecin. The impact to the natural envi- ronmental from the use of diesel fuel from vehicles was analysed. Based on the exhaust emission analysis this article shows the difference between using a fuel which emits less noise and is a cleaner energy source with high energy efficiency and the fuel used by carriers.