The new deal will keep Taddei at the Italian club until the summer of 2014.
The 30-year-old former Siena star has recently been linked with clubs such as Fiorentina, Valencia and Sevilla.
An official club statement read: “A.S. Roma and Rodrigo Ferrante Taddei wish to make public, with mutual satisfaction, an agreement for the extension of the player’s contract until the end of June 30, 2014.
“The player shall be awarded a fee of €2.8 million gross, for the seasons 2010-11, 2011-12 and 2012-13, and €1.9 million for the 2013-14 season, as well as individual awards for the achievement of set goals.”