Sports teams with offensive nicknames or logos should consider changing their identity, the head of the Anti-Defamation League has said.
Abraham Foxman's comments were made as part of the long-running debate on whether the Washington Redskins American Football team should be renamed.
He said efforts to combat discrimination and prejudice could be hampered by negative stereotypes in the NFL and other sports.
The use of "offensive caricatures and stereotypes of Jews and other minorities" had been "widespread" when American sports franchises were formed in the early 20th century, Mr Foxman said.
A discussion on the future name of the Redskins' franchise has divided opinion in Washington DC and across the US.
President Barack Obama suggested last week that he would consider changing the identity if he owned the team.
The nickname - and that of Cleveland Indians baseball team - has been seen as offensive to Native Americans.
In a statement made on Tuesday, Mr Foxman said team owners should discuss the issue with fans and then decide whether to "let go of this hurtful tradition".
"We believe the time has come for responsible sports enterprises to seriously consider moving away from the use of hurtful and offensive names, mascots and logos," he said.
"In the early 20th century, when many great American sports franchises were first named, offensive caricatures and stereotypes of Jews and other minorities were widespread in the mainstream media and popular culture.
"Today, offensive caricatures are no longer prevalent, public figures cannot utter ethnic slurs without repercussions, and we have come a long way in fighting discrimination and educating about the impact of prejudice."
Mr Foxman said sport was a "centrepiece" of culture and now reflected "inclusion, pluralism and equality" in a way it did not 60 years ago.
He concluded: "Unfortunately, however, some offensive caricatures persist.
"While it is not the intention of the fans, owners or leaders of sports franchises to offend, teams like the Washington Redskins and the Cleveland Indians have a responsibility to be sensitive to the legitimate hurt that offensive names, mascots and logos cause."
The ADL fights antisemitism and bigotry in the United States and around the world.
The debate over team names has echoes of the Y-word debate in Britain and arguments over Tottenham fans' use of the word "yid" in terrace chants.