North Carolina Republican Richard Burr and Democrat Kay Hagan, and South Carolina Republican Lindsey Graham had promised they wouldn't take paychecks if a budget impasse forced the federal government to shut down.
Republican Sen. Jim DeMint had said he'd give his pay to charity.
But President Barack Obama and congressional leaders forged an agreement late Friday night.
At least two dozen senators had promised to forgo a paycheck during a shutdown.
Burr and Graham had said they would contribute their salaries to the treasury.
Hagan said she'd donate pay during a shutdown to a North Carolina charitable organization for veterans.