In view of the fact that the technological progress is in a constant state of change, current research efforts are directed towards blockchain technology. Starting from the description of the way blockchain technology operates, the notions of decentralisation, proof-of-work consensus, and practical immutability are explained. Next, the author researches the new tax regulations in force in Poland since 1 January 2019 and concentrates on revenues from cryptocurrency trading, which are classified as revenues from money capital and revenues from capital gains. The article presents a definition of the disposal for valuable consideration of a virtual currency, explains how high is the income tax on income earned from the disposal for valuable consideration of virtual currencies, and provides an overview of the legislation related to tax deductible expenses. Finally, some reflections on the cryptocurrency trading in the context of the pursuit of an economic activity are given.