Condoleezza Rice made the announcement in a speech on Wednesday that outlined her hopes to transform the posture of US diplomacy to focus more on promoting democratic and economic change.
"It is clear today that America must begin to reposition our diplomatic forces around the world," the secretary told students at Washington's prestigious Georgetown University.
"So, over the next few years, the United States will begin to shift several hundred of our diplomatic positions to new, critical posts for the 21st century," she said.
"We will begin this year with a down payment of moving 100 positions from Europe and, yes, from here in Washington, DC, to countries like China and India and Nigeria and Lebanon, where additional staffing will make an essential difference."
The State Department, which Rice took over a year ago, counts some 7440 diplomats and other employees abroad, according to official figures.
Rice appeared at Georgetown University before hundreds of students and professors to explain the concept of "transformational diplomacy" preached by the administration of President George Bush.
"It is clear today that America must begin to reposition our diplomatic forces around the world"
US secretary of state
She said the policy was an attempt "to seek and support the growth of democratic movements and institutions in every nation and culture, with the ultimate goal of ending tyranny in our world".
"Transformational diplomacy is rooted in partnership, not in paternalism," she said, adding that it was based on "doing things with people, not for them".
Rice said the United States had to rebalance its resources, noting the State Department had the same number of people in a country like Germany, with 82 million people, as in India, with a population of one billion.
"There are nearly 200 cities worldwide with over one million people in which the United States has no formal diplomatic presence," she said. "This is where the action is today, and this is where we must be."