"I'm OK. I don't want to make any comments but I am OK," she said shortly after walking out of Tehran's Evin prison. She was then driven away by her father.
Barack Obama, the US president, welcomed what he called a "humanitarian gesture" by Iran.
"He was relieved to see that Roxana Saberi has been released," Robert Gibbs, the White House spokesman, said.
"We know this has been a trying time for her family and friends and he looks forward to welcoming her home to the United States.