Barely two months after her husband Bob's death, Doris Matsui (search) was sworn in Thursday to fill the Sacramento, Calif.-area House seat he held for 26 years.

"Despite tragedy and heartbreak life indeed does go on, and I know that somewhere Bob is looking down and smiling," the 60-year-old Democrat said in her first House floor speech after Speaker Dennis Hastert administered the oath of office.

Matsui joins three other widows serving in the House. Californians Mary Bono, a Republican, and Lois Capps, a Democrat, also replaced their husbands in Congress upon their deaths, as did Missouri Republican Jo Ann Emerson.

Bob Matsui (search), a leading Democrat who was an authority on Social Security and confidant of Minority Leader Nancy Pelosi, D-Calif., died Jan. 1 of complications from a rare bone barrow disease. He was 63.

His wife of 38 years announced her candidacy less than two weeks later. She overwhelmed her opponents in a 12-candidate field Tuesday, drawing 69 percent of the vote, far more than the over-50 percent needed to avoid a runoff.

A native of California's Central Valley, Doris Matsui worked in the Clinton White House as a deputy assistant to the president and deputy director of public liaison. Prior to her husband's death she was working as a lobbyist on issues including technology, telecommunications and health care.

Matsui planned to cast her first vote Thursday for a massive transportation bill being debated in the House. She said in an interview that she hopes to promote stem cell research, something that might have helped her husband, and join Democratic efforts to oppose President Bush's plan to change Social Security (search) by establishing private accounts.

But she said, "I cannot fill my husband's shoes. And besides that I wear a different kind of shoes."

Since 1923, 45 congressional widows have gone to Capitol Hill upon the death of their husbands.