Russ Feingold, D-Wis., engineered the surprise passage of the legislation, which would deny senators and members of the House an automatic pay raise of about $1,600 next year. Members of Congress make $174,000 a year.
The Senate passed the measure unanimously without a roll call vote. The House has yet to act on it, but probably will go along given election-year pressures.
Lawmakers receive an automatic cost-of-living pay hike unless they pass legislation to block it - as they did last year. The last time they opted to take the pay hike was in 2008, which meant they received a $5,000 raise last January.
Automatic pay raises were part of an ethics reform bill in 1989, and Congress at that time gave up its ability to accept pay for speeches and made annual cost-of-living pay increases happen unless the lawmakers specifically voted to stop them.
In the early days of GOP control of Congress, lawmakers routinely denied themselves the annual COLA. But they accepted the raise during most of the past decade.
Now, with unemployment at double-digit levels nationally and with Congress suffering from abysmal approval ratings, it's a no-brainer to decline the pay hike.
"Not many Americans have the power to give themselves a raise whenever they want, no matter how they are performing," Feingold said. "Yet Congress has set up a system whereby every year members automatically get a pay increase without having to lift a finger."
Most members, however, privately support the pay raise as a means of retaining experienced lawmakers and of making sure that Congress is not simply dominated by wealthy people. Many lawmakers maintain homes both in the expensive Washington housing market and back in their districts. On most days, they meet with lobbyists making far more than they do.
House Speaker Nancy Pelosi, D-Calif., makes $223,500 and Minority Leader John Boehner, R-Ohio, makes $193,400. President Barack Obama makes $400,000.