The Beijing samples - across all sports - are being sent to the World Anti-Doping Agency accredited laboratory in Lausanne, IOC spokeswoman Emmanuelle Moreau said.
The IOC conducted more than 5,000 drug tests during the Beijing Games.
The samples will be reopened and tested for CERA, a new generation of the endurance-enhancing hormone EPO. The substance boosts an athlete's performance by increasing the number of oxygen-rich blood cells.
Details of the testing procedure are under discussion with WADA, Moreau said.
The decision comes after a new lab test used by the French Anti-Doping Agency detected CERA during retesting of samples from Tour de France riders. The original urine tests had raised suspicions but proved inconclusive.
"It's very good. It allows us to confound the cheaters," Tour de France chief Christian Prudhomme said Tuesday. "What's being done at the Tour de France has never existed in the world of sport."
Officials confirmed Tuesday that German rider Stefan Schumacher, and Italians Riccardo Ricco and Leonardo Piepoli had tested positive for CERA at the Tour. The three riders combined to win five of the Tour's 21 stages.
IOC vice president Thomas Bach said Tuesday that the future of men's road cycling in the Olympics could be threatened unless the sport cleans up its act under the aegis of the international cycling union, or UCI.
If the entire sport doesn't pull together to improve the situation, "then you have to consider giving men's road cycling a pause" from Olympic participation, Bach told The Associated Press in a telephone interview.
In a statement Wednesday, Moreau said, "The IOC will continue to support the UCI - and any other international federation - as long as it is deploying meaningful and credible means and efforts to fight against doping."
The IOC disqualified six athletes for doping during the Beijing Games - Ukrainian heptathlete Lyudmila Blonska, Ukrainian weightlifter Igor Razoronov, Greek hurdler Fani Halkia, North Korean shooter Kim Jong Su, Spanish cyclist Isabel Moreno and Vietnamese gymnast Thi Ngan Thuong Do.
Three other cases are still pending. The IOC has given Belarusian hammer throwers Vadim Devyatovskiy and Ivan Tsikhan until Oct. 17 to provide more information explaining why they tested positive for testosterone. A decision is due shortly in the case of Polish canoeist Adam Seroczynski, who tested positive for clenbuterol.