In the same low-key style that has characterized his 23 years in the U.S. Senate, Paul S. Sarbanes sauntered into the Annapolis elections headquarters yesterday and filed for reelection, a bid that could make him Maryland's first senator to serve five terms.

"This is the time you come back to the people and account for your stewardship," he said. "We've tried to serve with integrity, common sense and independence of judgment, and I think we've performed well."

Sarbanes, 66, is 12th in seniority in the Senate and is the ranking Democrat on the Senate Banking, Housing and Urban Affairs Committee. He recently was involved in steering banking legislation to approval that requires banks to lend money in poor neighborhoods where they have depositors, and revamps the rules that kept separate banks, securities firms and insurance companies.

He also has played a part in environmental legislation directed at restoring the water quality and habitat of the Chesapeake Bay and the Potomac River.

The Baltimore lawyer, who has spent most of his adult life in elected office, first as a state delegate and then as a member of Congress, said he wants to serve another term in the Senate to focus on priorities such as improving education, protecting the environment and creating jobs.

Sarbanes had raised $663,384 as of June 30 to finance the 2000 campaign, according to Federal Election Commission records. He had raised far more than any of his opponents at that point. More than one-quarter of that has come from finance and insurance interests, according to an analysis by the Center for Responsive Politics, which tracks campaign money.

With two weeks remaining before the filing deadline, one other Democrat and six Republicans have filed to challenge him.