Abstract: A system for carrying out a prepayment for products or services acquired through electronic means of the comprising an electronic network where at least one products or services supplier's electronic terminal and at least one buyer's electronic terminal are connected thereto is disclosed. The system also includes at least one prepayment electronic terminal able to generate a financial instrument of payment with an identification number associated with an amount prepaid by a buyer and to a security code; a data storage electronic terminal connected to both, the prepayment electronic terminal and the other computers of the electronic network, said data storage electronic terminal including a data base in which the financial instrument of payment identification number together with its security code and the prepaid amount associated therewith are registered.