The Trading of Cryptocurrencies from the Perspective of European Private International Law. The rules in the Rome I Regulation are used to ascertain the applicable law in cases of trades in cryptocurrencies. However, these are only partially appropriate for a predictable determination of the applicable law. While in B2B and C2C cases of “stationary” trading of cryptocurrencies via Crypto-ATMs the law at the location of the ATM still provides a predictable legal system, this is not the case for online trading with crypto-brokers or via crypto exchanges. Especially in cases of online trading via crypto exchanges, a further complication results from the fact that such platforms allow their users to trade legally under a pseudonym – in line with the historical notion of cryptocurrencies. This may complicate or even prevent the determination of the applicable law. The resulting “vacuum” is to some extent filled by the technical design of the transaction through the use of smart contracts. However, this does not dispense with the question of applicable law. The article examines these and other questions and points out possible solutions de lege lata.