The Washington Post Co. elected Melinda French Gates -- a former Microsoft Corp. executive and wife of founder Bill Gates -- to its board yesterday, adding the spouse of the world's richest person to a 10-member board that already includes the world's second-richest person, Warren E. Buffett.

Melinda Gates worked at Microsoft from 1987 to 1996 and developed multimedia products. In 2000, she and her husband launched the Bill & Melinda Gates Foundation, which has given away billions of dollars in educational and health-related aid to Third World countries for work on such initiatives as new vaccines and HIV-prevention programs.

The foundation is worth $27 billion, three times the size of the Ford Foundation. Forbes magazine named Bill Gates the world's wealthiest person, estimating he alone is worth $47 billion; the couple have vowed to give away 95 percent of their wealth in their lifetimes.

"She's a well-qualified director, somebody with a good strong business and technology background, and helps to run a very large organization," said Post Co. Chairman Donald E. Graham. "We feel fortunate to be able to add her to our board."

Graham said The Post Co. approached Gates about the position over the summer. Her appointment does not signal any new direction for the $8.9 billion company, Graham said.

Melinda Gates was traveling yesterday and unavailable for comment, but Gates family spokesman Joe Cerrell said, "I think Melinda's business background combined with her current role in shaping the direction of the Gates Foundation should be a valuable contribution to this board."

During a 2003 humanitarian trip to Africa, Melinda Gates described why the couple are willing to part with so much of their wealth: "Yes, Bill worked really hard and he's been incredibly smart about some things, but also very, very lucky. Given that, we both feel a huge responsibility to do what we can with that resource."

Melinda Gates, a 40-year-old Texan, joins other prominent Post Co. board members, including interactive shopping guru Barry Diller, former White House budget director Alice M. Rivlin and Buffett, the Berkshire Hathaway Inc. chairman whose wealth is estimated by Forbes magazine at $43 billion.

Buffett is a longtime friend of Bill Gates and his father, William H. Gates II.

Post stock closed at $920.01 per share yesterday, up $25.01 on the day's trading.

Melinda Gates also sits on the board of Drugstore.com Inc., an online drug-selling company, and holds 2.7 million shares of that company's stock, 3.4 percent of the total. In June, chief executive Kal Raman resigned and the company told analysts that its 2004 losses would be greater than expected.

Two weeks later, New York class-action specialty firm Milberg Weiss Bershad & Schulman LLP sued Drugstore.com, saying insiders such as Raman knew about the company's poor performance and sold millions of dollars in stock while issuing positive forecasts. Melinda Gates is not named in the suit. Drugstore.com spokesman Walter Conner said the company does not comment on pending litigation; Melinda Gates's spokesman also declined to comment.

Melinda Gates also was on the board of trustees of her alma mater, Duke University, where she earned a computer science degree, and has been an adviser to ThirdAge Inc., an online content company that caters to baby boomers. She no longer serves in that capacity.

The mother of three resigned from the Duke board in May, telling fellow trustees in a letter that traveling from Seattle to Durham, N.C., for board meetings four times a year was no longer "feasible" given her extensive overseas travels for the foundation.

The Post Co. board meets six times a year, five times in Washington and once in New York.

"Melinda has personal relationships and other business on the East Coast related to the Gates Foundation that makes D.C. perhaps a more convenient location for her," Cerrell said.

Like all non-employee Post Co. directors, Gates will receive $60,000 annually and be reimbursed for expenses related to board meetings, according to the company proxy statement.

Gates will not serve on any board committees initially, Graham said.

In addition to The Washington Post, The Post Co. owns six television stations, Newsweek magazine, the Kaplan Inc. education company and several smaller newspapers -- including the Everett (Wash.) Herald and the suburban Washington Gazette papers. The company also owns washingtonpost.com and Cable One Inc., a small cable company with about 712,000 customers throughout the South and Plains states.

Staff researcher Richard Drezen contributed to this report.

Melinda Gates and husband Bill Gates launched a charitable foundation now worth $27 billion.