The fact of a very large gap between the prices of petrol and gas induces an ever-increasing number of drivers to use LPG. The estimates show that in 2009 over 2.5 million vehicles equipped with LPG systems moved on Polish roads. We should ask ourselves whether the prices of LPG will also increase? It is possible, but for obvious reasons, LPG will never be more expensive than oil. Gas is a by-product of the crude oil refining process. The status of waste and by-product imposes certain limitations when fixing the price of the fuel. As projected by the Gazeo.pl portal, prices of gas will always be lower than those of oil by 40-60%. Since the moment of appearance of LPG systems in the Polish market, i.e. since 1990s, their popularity have been continuously increasing. In 2004, Poland became a worldwide leader in the LPG market in terms of the number of LPG systems installed in cars.