The tax on hydrocarbons is a special tax of manufacture of indirect nature that taxes the consumption of hydrocarbons and includes all products that are intended to be used as fuel for heating (except coal) or as fuel in any type of engine (article 46 of Ley 38/1992). The main energy products that are subject to tax by the tax on hydrocarbons are: gasoline, kerosene, diesel, fuel oils, liquefied petroleum gases, natural gas, biofuels and biofuels, when they are intended for use as fuel or fuel. The tax base is constituted by the volume of products subject to the tax.

The tax on hydrocarbons has the character of concerted taxes that is governed by the same substantive and formal rules established in Ley 38/1992. However, the Historic Territories can establish the tax rates within the limits and under the conditions in force at any time in the common territory. It is required by the respective Foral Councils when the accrual occurs in the Basque Country (article 33 of Ley 12/2002 and Ley 7/2014).