This article presents an initial attempt to assess the impact of new regulations impacting the system of taxation on the profitability of unconventional gas production. The new system of fiscal burdens for entrepreneurs involved in the exploitation of hydrocarbons in Poland will be introduced from 1 January 2015, but payment of these taxes will be deferred to 2020. This fiscal system will consist of three basic elements – a special hydrocarbon tax, natural gas production tax, and corporate income tax (CIT). Two variants of an investment project were assessed – variant I, duration time 6 years and total production of natural gas of 56 million cubic metres; and variant II, duration time 20 years and total production of 100 million cubic metres of natural gas. A stochastic economic model was constructed using the Monte Carlo simulation to conduct the analysis. Results of the assessment show that the impact of the new tax regulations on the profitability of unconventional gas production projects will depend on their quality. In the case of variant I, the impact of the new regulations is small. For variant II, where greater total production and duration time is assumed, the negative impact of the new regulations on economic efficiency is clearly visible. The progressive nature of the proposed changes is apparent; the more successful the production project, the greater the impact of the new tax system on its profitability. In variant I, the average net present value (NPV) for the new regulations increased by 1.65%, while for variant II it dropped by 14.10%. The nominal average value of the fiscal burden for variant I decreased by 0.36%, but for variant II increased by as much as 66.16%.