Iraqi judoka Sajjad Ghanim Sehen Sehen was provisionally suspended on Friday after he tested positive for anabolic steroids, the International Testing Agency said on Friday.
The athlete, who can request a test of a B sample, has been banned from any activity during the Paris Olympics.
The ITA, which is in charge of anti-doping tests during the Games, said the judoka's sample dated from July 23, with the positive test reported two days later.
Should the second sample also test positive for the prohibited substances, he could face a ban of up to four years.
The Iraqi had been due to take on Uzbek Sharofiddin Boltaboev on July 30 in the under 81kg category elimination round.