Uncertainties about the tax treatment of business transactions in the tax return or tax balance sheet can cause significant accounting challenges for current and deferred taxes in the financial statements. Whereas the accounting treatment of tax risks or tax audit risks has been regulated under US GAAP since 2006, a corresponding IFRS regulation was only published in 2017 and is effective from the 2019 fiscal year. The author takes this as an opportunity to analyze and critically assess the differences between the US GAAP accounting regulation “FIN 48 – Accounting for Uncertainty in Income Taxes” and the IFRS accounting regulation “IFRIC 23 – Uncertainty over Income Tax Treatments”. Building on the insights from her analysis, the author also examines the problem areas arising from IFRIC 23 from the perspective of the German tax authorities, German business practice and German advisory practice.