The representatives said Tuesday they've sent letters to Redskins owner Dan Snyder, NFL Commissioner Roger Goodell, Redskins sponsor FedEx and the other 31 NFL franchises.
The letter to Snyder says that "Native Americans throughout the country consider the 'R-word' a racial, derogatory slur akin to the 'N-word' among African Americans or the 'W-word' among Latinos."
Among the group sending the letters are the leaders of the Congressional Native American Caucus: Tom Cole, R-Okla., and Betty McCollum, D-Minn.
The nickname is the subject of a long-running legal challenge from a group seeking to have the team lose its trademark protection.
Snyder has vowed that he will never change the name.