The State Department said Powell expressed hopes for a stable and democratic Georgia, United Press International reported.
Burjanadze formally replaced Eduard Shevardnadze earlier Sunday after the embattled former president agreed to step down following a widespread protest in the Georgian capital, Tbilisi.
The United States, the department said, "stand(s) ready to support the new government in holding free and fair parliamentary elections in the future as required by the Constitution."
Referring to the widespread protest that forced Shevardnadze out, the department said, "The people of Georgia have heard the call of Mikheil Saakashvili and his colleagues in the opposition to move to a new stage in Georgian politics."
The State Department also praised Shevardnadze, saying: "We know that President Shevardnadze's decision was difficult, but that he made his decision in the best interests of the people of Georgia."