Abstract: A coin security system is provided which electronically monitors coins passing into a portable coin collection security bag in order to discourage pilferage of coins stored in the collection bag. A memory chip associated with the bag, or with a mounting member connected to the bag, is in communication with the central data processor in the vending machine circuit when the collection bag is mounted and is receiving coins. When the portable collection bag is disconnected, the memory chip becomes disconnected from the circuit and breaks the circuit, causing the vending machine to shut down. This automatic shutdown feature reduces another kind of pilferage by discouraging the depositing of coins into the vending machine when the coin collection security bag is not in place.