This paper addresses the legal regime applicable to casesin which there is a use of a bank card or trading house by athird party without the consent of the owner. It begins by explainingthe comparative experience, and then referring to the Chilean legalsystem. In this regard, it is postulated that after the notice of loss ortheft made by the cardholder, all costs must be paid by the supplier,unless it is proved that they were made by the owner himself. Bycontrast, the previous charges, are borne by the consumer, unless itis proved that the misuse of the card, was due to a negligent act ofthe provider, in which case the latter should respond.El documento aborda el régimen jurídico aplicable a aquellos casos en los cuales existe el uso de una tarjeta bancaria o de casa comercial por parte de un tercero, sin el consentimiento del titular. Se comienza explicando la experiencia comparada, para luego referirse al Ordenamiento Jurídico Chileno. A este respecto, se postula que los cobros posteriores al aviso de extravío o hurto que hiciere el tarjetahabiente, son de cargo del proveedor, salvo que se acredite que fueron realizados por el propio titular. Por el contrario, los cobros anteriores, son de cargo del consumidor, salvo que se pruebe que el mal uso de la tarjeta, se debió a un acto negligente del proveedor, en cuyo caso, éste último debe responder.