The battle against money laundering and terrorism financing depends largely on the use of technology as a tool for the detection of potential money launderers. In this article, we aim to show that the use of technology not only offers a number of opportunities in terms of fighting financial crime, but also impacts on fundamental rights. We will illustrate this by describing the current practice of transaction monitoring within banks. Furthermore, we will discuss two specific illustrations of these impacts: the Swift-case, representing the exchange of information on European citizens and their transactions with the US government on the one hand, and the Patricia Vinck-case, illustrating the question of privacy and proportionality with regard to the fight against money laundering on the other hand.