European Union data protection law aims to protect individuals from privacy intrusions through a myriad of procedural tools that reflect a code of fair information principles. These tools empower the individual by giving him/her rights to control the processing of his/her data. One of the problems, however, with the European Union’s current reliance on fair information principles is that these tools are increasingly challenged by the technological reality. And, perhaps nowhere is this more evident than when it comes data mining, which puts the European Union data protection principles to the ultimate test. As early as 1998, commentators have noted that there is quite a paradoxical relation between data mining and some data protection principles.This paper seeks to explore this so-called paradoxical relationship further and to specifically examine how data mining calls into question the purpose limitation principle. Particular attention will be paid to how data mining defies this principle in a way that data analysis tools of the recent past do not.