This essay considers the coin finds in the mithraeum of Duino and discusses the various hypotheses that have been put forward to explain the reasons for an abundant presence of coins in the mithraeum. While a ritual use of coins within this cave between the 1st and 3rd century cannot be ruled out, the absence of precise archaeological contextual data and the very composition of the monetary nucleus, mostly comprised between the mid-4th and early 5th century, lead to the exclusion of an economic defunctionalization in favour of a ritual one. Instead, the concealment of a hoard, later tampered with during the first digging works and subsequent archeological excavations, appears much more evident on numismatic grounds.
