All five were elected in November.
Republican Roger Wicker of Tupelo will serve a six-year term in the Senate.
The House members serve two-year terms. They are Democrat Bennie Thompson of Bolton in the Delta's 2nd District and Republicans Alan Nunnelee of Tupelo in the northern 1st District, Gregg Harper of Pearl in the central 3rd District and Steven Palazzo of Biloxi in the southern 4th District.
The state's senior senator, Republican Thad Cochran of Oxford, is beginning the fifth year of his current six-year term. Cochran was first elected to the Senate in 1978 and hasn't said whether he'll seek re-election in 2014.
Cochran was chosen Thursday to be the top Republican on the Senate Agriculture Committee. He has served on the committee since joining the Senate, and he was the committee chairman from 2003 through 2005, when Republicans held the Senate majority.
"I will use the experiences I've gained in serving on the committee since 1979 to help quickly advance a new Farm Bill that will meet the needs of our country's farmers, small businesses and those who rely on the nutrition programs under the Committee's jurisdiction," Cochran said in a news release Thursday.
For the past six years, Cochran has been the ranking Republican on the Senate Appropriations Committee, which he previously chaired. He gives up the leadership role on Appropriations, but remains a member of the powerful committee that decides how federal dollars are spent. Cochran also remains a member of the Senate Rules Committee.
Wicker on Thursday was named deputy whip for the Republicans in the Senate. In that post, he'll help count votes and build support within the Senate for the party's agenda. He said in a news release that he wants to help reduce federal regulation and promote U.S. energy production to help spur economic growth.
"We face a number of challenges that require leadership and cooperation to solve," Wicker said. "Congress and the President must reduce the federal deficit and begin to address the debt. At $16.4 trillion, the debt is unsustainable, and the problem gets worse each day. All sides need to have an honest discussion about what we can afford and what we can do without."