Darya Klishina, the only Russian due to compete in the athletics at the Rio Olympics, has been banned from taking part.
The long jumper had originally been cleared to compete at the Games as the IAAF was satisfied that she was clean.
Klishina's drugs-testing record was established in the United States, where she is based, rather than in Russia, but the governing body has now revoked her eligibility based on new, unspecified information.
"I have proved that [I am clean] already many times and beyond any doubt," Klishina wrote on her Facebook page.
"I am falling victim to those who created a system of manipulating our beautiful sport and is guilty of using it for political purposes.
"I will take every possible effort to protect my clean image."
Track and field athletes from the Russian Federation were banned en masse from the Olympics following claims that the country ran a state-sponsored doping programme.