Due to the success of shale gas developments observed in the US and the absence of domestic legislation specifically for unconventional gas projects in the countries, an arising question is whether replicating the fiscal terms conceptually conceived for conventional oil and gas exploration would be appropriate for the exploitation of unconventional gas deposits. To assess this issue, this study approached the question with a fiscal policy formulation perspective. It was assumed that a desirable fiscal system, able to balance opposed objectives from the Government and private investors would be a flexible, neutral and stable one, favourable to maximize the present value of the project. To address the question, this article makes a comparison between shale gas projects and conventional gas projects to examine if they have structures similar enough to be covered by the same fiscal regime or if the legislation needs to cover issues that are exclusive to shale gas projetcs. The analysis showed that, first, the basis of comparison would be better segmented between oil projects and gas projects – either from conventional or unconventional sources, since this last category has less margin of rent available to be taxed. Besides that, shale gas projects have particularities that should be considered by policy makers when designing a fiscal system to encourage its development. Furthermore, fiscal instruments can be a powerful tool to guide tax payers behavior and hence address other concerns not necessarily related to revenue-raising, bur, for example, environmental and social issues.