Sentencing is March 29 for 33-year-old Fernando Hernandez of Dallas.
Prosecutors say Hernandez on Tuesday pleaded guilty to receiving a bribe by a public official. He also could be fined up to $250,000.
Investigators say Hernandez was arrested Oct. 9 at his IRS office over a June 2005 incident in which he sought and accepted a $2,000 bribe from a taxpayer.
Details on who paid the bribe were not immediately released.
Hernandez, who no longer works for the IRS, was free on a personal recognizance bond.