Olympic chiefs will step up their war on the drug cheats by carrying out blood sampling at all events in Athens.
More than 3000 drug tests will be carried out in Athens
"It's the first time there will be blood tests across all sports," an International Olympic Committee official confirmed on Thursday.
Blood testing was previously limited to endurance sports, which were screened for the blood-boosting synthetic hormone erythropoietin (EPO).
More than 3,000 tests will be conducted at Athens, a 25% increase from Sydney.
Blood samples taken from athletes will also be frozen and stored for potential retroactive tests.
The top four athletes in all events will be tested as well as a random selection of other competitors.
Testing in Athens will be carried out at a World Anti-Doping Agency accredited laboratory with a staff of 120.