Method for detecting possible frauds in payment transactions between at least two partners (1, 2), the payment transaction data and/or payment authorization data being transmitted over at least one mobile radio network, at least one multivalued parameter used for detecting a possible fraud attempt being determined in said mobile radio network, said payment transactions being performed over at least one payment service provider (4), at least a second multivalued parameter used for detecting a possible fraud attempt being determined by said payment service provider (4), and certain combinations of said first and second parameters are sought in said fraud detection module in order to detect fraud attempts.