A growing share of illicit drug distribution takes place using cryptomarkets that use encryption and anonymization technologies. The risks of law enforcement intervention and violence are lower here than in off-line traditional drug markets, but with the technological innovations follow new opportunities for stealing and fraud. The sites themselves fall prey to theft and hacking attempts, administrators abscond with users’ funds, and malicious sellers regularly cheat buyers. In this study, we explore the types of theft and fraud that occur on cryptomarkets using multiple data sources: formalized community resources (e.g., guides, tutorials), ethnographic observations of user forums, thematic identification of forum posts using unsupervised text classification, and an expert interview. We find system-based violent predatory resource exchange similar to robberies and process-based fraudulent resource exchange similar to rip-offs. We discuss these offenses conceptually as extensions of common drug-related crimes in the digital world. This contributes to the research on how cryptomarkets work and can improve crime-prevention efforts.