The announcement came only hours after clashes erupted in Athens as protesters rallied to condemn the planned visit.
Marchers shouted angry slogans against the Bush administration and its operations in Iraq and Afghanistan.
A spokesman for the department, Kurtis Cooper, was quoted by the Associated Press news agency as saying the anti-American protests in Athens had “played no role” in Mr Powell’s decision.
Protests in Athens continued into Saturday with an anti-Powell banner appearing on the city’s most famous monument, the Parthenon.
