Online anonymous marketplaces are commercial marketplaces that run on the dark web (parts of the web accessible only through anonymizing software such as Tor). Buyers and sellers preserve anonymity by using cryptocurrencies and PGP. As a result these marketplaces are used primarily for illegal activities such as sales of drugs. There are many such marketplaces, and in 2015, researchers obtained information on more than 20,000 seller accounts (Soska and Christin 2015). Sellers can operate accounts on different marketplaces, or multiple accounts on the same marketplace. In this work, we explore methods to match these accounts, to determine which of them in fact correspond to the same real-world entities. This would give a more precise measurement of the number of players active in these marketplaces over time. Information that we use includes sellers’ profile description, types of products sold, countries shipped from/to, item listings, as well as customer feedback.