Senate Minority Leader Mitch McConnell (R-Ky.) picked Republican Sens. John Kyl (R-Ariz.), Pat Toomey (R-Pa.) and Rob Portman (R-Ohio).
House Speaker John Boehner (R-Ohio) chose Reps. Jeb Hensarling (R-Texas), Dave Camp (R-Mich.) and Fred Upton (R-Mich.). Hensarling will serve as the Republican co-chair of the committee.
They will join Senate Majority Leader Harry Reid's appointees: Sens. Patty Murray (D-Wash.), John Kerry (D-Mass.) and Max Baucus (D-Mont.). Murray will serve as the Democratic co-chair of the committee.
Hensarling is a five-term congressman from the Dallas area, and he is also chairman of the House Republican Conference. He gets high marks from conservative groups for opposing taxes and abortion, while supporting gun rights.
Murray is chairwoman of the committee to elect Democratic senators and a longtime protector of Democratic priorities such as Medicare, Social Security and veterans' benefits.
House Minority Leader Nancy Pelosi hasn't yet made her selections.
The committee is charged with coming up with at least $1.2 trillion in budget savings over the coming decade. It has until the day before Thanksgiving to come up with a plan that gets at least seven votes.
If it fails, or if the House or Senate votes down its recommendations, severe across-the-board spending cuts would be triggered automatically, hitting large swaths of the federal budget starting in 2013, including priorities dear to both parties. These include Medicaid, farm subsidies and the defense budget.
The Associated Press contributed to this report.