A method for operating an automated teller machine (1) after that a card (2) has been inserted by a user into a card reader (14) of the automated teller machine (1) for performing a transaction involving the card (2), comprises the following steps, performed by a processing unit (11) of the automated teller machine (1): when the transaction is over, instructing the card reader (14) to release the card (2) (b); if the card (2) is not taken out from the card reader (14), determining whether the user is present or not in front of the automated teller machine (1) (c); if it is determined that the user is not present in front of the automated teller machine (1), instructing the card reader (14) to swallow the card (2) (d).