The taxation of bitcoins and similar cryptoassets is of immense economic importance to the individual taxpayer and to society as a whole. In recent years, they have effectuated a number of tax law issues in Denmark. In Norway, Sweden, and Denmark, the taxation of bitcoins and similar cryptoassets is based on the general rules of tax law. This article contains a comparative analysis of the three Scandinavian countries’ tax treatment of gains and losses on them. The analysis shows that the Norwegian and Swedish rules that have been significantly changed and modernized do not at all present the same challenges as the Danish rules. In Denmark, there is need for uniformity, predictability, and clarity to be introduced into the taxation rules. Therefore, the article also provides some reflections how to change the Danish tax legislation. Bitcoins, cryptocurrencies, cryptoassets, capital gains taxation, Danish income tax, Norwegian income tax, Swedish income tax, speculation taxation