DURHAM, N.C. — The first woman to become president of Duke University said Sunday she will leave her job at the elite, private university next year.

Nannerl O. Keohane, 62, will have spent 11 years running Duke once she steps down in June 2004. She said at a news conference Sunday she hoped the university's trustees choose a successor with "a sense of humor, stamina and a high tolerance for stress."

Keohane, a political science professor, came to Duke from the presidency of Wellesley College.

Under her leadership, Duke launched programs in fields ranging from genomics to ethics. She helped raise more than $2 billion from patrons and establish the Duke University Health System, a three-hospital regional system centered on Duke University Medical Center.

"It has been a privilege to lead Duke University," Keohane said in a letter to the Duke community, "and I have treasured this experience.

"The past 10 years have been very rewarding for me personally and professionally. Now, with our bold strategic plan firmly in place, the Campaign for Duke scheduled to conclude in December and a strong administrative team in office, I believe it's a good time for Duke to move into the next stage of its history as an institution."

Keohane said she had wrestled with her decision since June of last year and discussed it with her husband, Robert, a Duke political science professor, and a few close friends.

She said she wanted "several years of active involvement in teaching and research as a political theorist before I retire altogether."

Keohane said she told Harold "Spike" Yoh, who chairs the university's board of trustees, and the board's two vice-chairs of her decision in December. They agreed to announce it publicly only after Keohane informed the full board during its meeting on Saturday.

"Nan Keohane has been one of the most innovative and successful presidents not only in the history of Duke, but across the country," Yoh said. "Duke has blossomed under her leadership, becoming more than just a great regional university to join the top rank of universities anywhere."

The board's vice-chair, Robert K. Steel, will head a search committee to select Keohane's successor. Steel is a vice chairman of investment banking and management firm Goldman Sachs & Co.

The Keohanes plan to take a one-year sabbatical away from Duke after she steps down. That would allow the incoming president to start work without the former president in the wings, Nan Keohane said.

"I believe it's a good time for Duke to move into the next stage of its history as an institution, and for me to move on to the next stage of my life," Keohane said in a statement to Duke's faculty and students.

Keohane was born in Blytheville, Ark., and is a 1961 graduate of Wellesley. She earned advanced degrees at Oxford University and Yale University before joining Swarthmore College as a political science professor.

She worked at the University of Pennsylvania and Stanford University before returning to Wellesley as its president in 1981.