'I think that an overwhelming proportion of the intensely demonstrated animosity toward President Barack Obama is based on the fact that he is a black man, he's African-American,' Mr Carter told NBC television.
'I live in the South, and I have seen the South come a long way,' he added.
'But that racism inclination still exists, and I think it has bubbled up to the surface because of a belief among many white people, not just in the South but across the country, that African-Americans are not qualified to lead this great country.'
'It is an abominable circumstance, and grieves me and concerns me deeply,' the former president said.
Mr Carter's remarks come after a week in which a Republican Congressman Joe Wilson shouted 'You lie' at the US president during a speech, and thousands protested against Obama administration policies in Washington.
A series of Democratic lawmakers and political columnists have pointed to the trends - the heckling, the gun-toting, the preachers leading congregations in prayers that Obama will die - and warned of the danger therein.
