Abstract: The invention relates to a procedure for processing data, especially transaction data, in an electronic payment system, whereby the electronic payment system includes a minimum of one payment terminal, a collections device and a transaction system. During the procedure, a data record is generated with header data (1), a payment transaction is executed by the minimum of one payment terminal (2), information concerning the payment transaction is stored in the data record (3), the data record is flagged as a shadow data record (6), and an additional data record with additional header data is generated (7), whereby the additional data record is generated before a further payment transaction (8) begins.