Long term storage of the anti-doping samples and their reanalyses becomes today more and more a trend in the anti-doping community. The procedure has been implemented by the anti-doping authorities for the samples of the Tour de France and for the Olympic Games since Athens 2004 and has been always presented as a good tool to deter doping habits in top level sport. Recently, the World Anti-Doping Code introduced the possibility for anti-doping organizations to store the athletes’ samples up to ten years. The anti-doping authorities may ask to reanalyze the samples at any time during that period of time as a function of the implementation of new methods or instruments in the accredited laboratories allowing the detection of prohibited substances or their metabolites at a much lower concentration or for a larger detection window. The most significant technological advances for the detection of doping substances have been done in the characterization of various long-term metabolites of anabolic androgenic steroids. This allowed for increasing the time of detection by even a factor of four.