Abstract: The invention relates to a system for inhibiting fraud in relation to the use of negotiable instruments and, particularly, in relation to cheques and credit cards. The system requires the owners of cheques and credit cards to be registered with the system, as well as the presentees to whom cheques and credit cards are presented. Via an authorisation and verification procedure to be followed respectively by owners and presentees, particularly by communicating with a central communication and processing unit, fraud in relation to the presentation of cheques and credit cards can be largely eliminated. Communication with the central communication and processing unit will be via telephone lines, although adaptation to accommodate internet communication also is envisaged.