Cryptocurrencies are a form of digital asset used as a medium of exchange, using cryptography as a way to secure transactions, control the creation of additional currencies and to confirm currency transfers, and are defined as a subset of digital currencies, alternative currencies and virtual currencies. Cryptocurrencies, more precisely their use for criminal purposes, represent a serious, insufficiently researched security challenge in criminalistic theory and practice. However, today we can talk about certain, hitherto observed specifics and characteristics of cryptocurrencies: unregulated legislation, decentralization, anonymity, cryptography, blockchain technology, the fact that the issuance of cryptocurrencies is not controlled by the state, that there is no prescribed way to create cryptocurrencies, global distribution, and data showing that a large percentage of cryptocurrencies are used for illegal purposes. Furthermore, the crimes that can be related to the use of cryptocurrencies are very wide and involve a large number of incriminations such as: money laundering, terrorist financing, malware, ransomware, phishing, tax fraud, extortion, blackmail, kidnapping, trafficking through illegal platforms for online trade of various types of goods such as drugs, weapons, counterfeit money, credit cards, documents, child pornography, networks of infected computers (botnets), and trade in various services and the like. The aim of the paper published in the journal: “Criminalostic Theory and Practice” was to point out the specifics that arise when investigating criminal offenses in which cryptocurrencies were used and the specifics of the analysis of evidence and seizure of cryptocurrencies.