Thanks to their low density, to their excellent processability and recyclability, and to their outstanding chemical resistance and specific mechanical strength, polymers are now the best materials to be applied in fuel tank systems. In that field, High Density Polyethylene (“HDPE”) is regarded as the best compromise between economical and technical requirements. But, basically, because of its chemical nature and structure, HDPE offers a poor barrier to hydrocarbons, especially light ones composing gasoline. Then, in order to meet to more and more demanding regulations on air quality and emissions, professionals from the Fuel Tank System area have developed several technologies in order to cope with that property of HDPE.The aim of that article is to present the different technologies that have been industrially developed and to compare their performance in terms of barrier properties. A quick overview of the present and next to come regulations is also included; as the choice for a barrier technology always have to refer to a given regulation: what can be proposed in one region can be absolutely satisfying the local regulation, and could maybe not applied in an other region, either because of different regulations (consider the case of Europe and US) or because of local policies which have an effect on the fuel composition (situation of Brazil compared to Europe or to the US for instance).