The Korean teams marched together in Athens when relations were better
The Olympic teams from North and South Korea will not march together at the Games' opening ceremony in Beijing, IOC President Jacques Rogge has said.
Rogge said leaders from the North and South could not agree on a joint march.
Athletes from the two countries marched under a "unification flag" in 2000 and 2004, wearing the same uniforms.
But relations have soured this year since South Korean President Lee Myung-Bak turned away from his predecessors' "sunshine policy" towards the North.
Rogge said the failure of last-ditch talks in Beijing aimed at bringing the two teams together for the opening ceremony was a "setback for peace and harmony and reunification".
He told a news conference in Beijing that there had been a "great willingness" among the two national Olympic committees to march together.
The two teams will walk one after the other at the ceremony, Rogge said, according to the usual way of ordering the teams alphabetically.
The frosty relations have forced China to drop a plan to have President Lee sit next to North Korean deputy leader Kim Yong-nam at a welcome lunch on Friday.
Relations had been slowly improving between the two countries until President Lee took office in February, promising to take a tougher line against the North.
And things took a further turn for the worse in July when a South Korean tourist was shot and killed by a Northern soldier after she allegedly strayed into a military zone near Mount Kumgang, a special tourist zone in the North.
Earlier this week, Pyongyang announced it would expel some of the South Korean workers at the resort, blaming President Lee for the downturn in relations.
The mountain resort had been regarded as one of the symbols of reconciliation between the two Koreas.
They have been technically at war since the 1950-53 conflict ended without a peace treaty.
The North has sent 60 athletes to China, its closest political ally; while the South has sent about 260.