Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are often used by athletes as doping agents. It is estimated that up to 25% of sportsmen using anabolic-androgenic steroids also take GH. Available data do not confirm the influence of GH or IGF-1 preparations on physical performance improvement. However, there is some evidences for many adverse effects in athletes using this form of doping. Blood tests to detect growth hormone abuse are available since several years. Surprisingly, no one has been proven to use illegal doping agents influencing GH/IGF-1 axis.