This study aims to assess the efficiency of the fossil fuel taxation scheme currently in effect in Switzerland. To this end, the concept of implicit CO2 prices is introduced, based on which prices for different fossil fuel uses are derived. Implicit CO2 prices are defined as the difference between actual prices paid by consumers and efficient domestic fuel prices. Efficient domestic fuel prices, in turn, consist of private production costs, a uniform value added tax and only local external costs, not including external costs due to CO2 emissions and global climate change. The resulting prices differ substantially, which suggests that there is considerable cost-saving potential in reducing CO2 emissions in Switzerland. For passenger cars and air traffic, the implicit prices are negative. For these uses, higher fuel charges would therefore be beneficial from a purely domestic perspective, i.e., without considering the negative repercussions of global warming. (C) 2016 Elsevier Ltd. All rights reserved.