Clinton holds a substantial lead over Obama among black women.
WASHINGTON (CNN) - Sen. Hillary Clinton's lead over Sen. Barack Obama, her chief rival for the Democratic presidential nomination, is growing among African-American voters who are registered Democrats, and particularly among black women, a poll said Wednesday.
Among black registered Democrats overall, Clinton had a 57 percent to 33 percent lead over Obama.
That's up from 53 percent for Clinton and 36 percent for Obama in a poll carried out in April.
Among white registered Democrats, Clinton drew 49 percent support, versus 18 percent for Obama and 17 percent for former Sen. John Edwards of North Carolina, the latest poll found.
The question had a sampling error of plus-or-minus 6.5 points.
The former first lady's strongest support among blacks came from black women, 68 percent of whom identified her as their likely choice, versus 25 percent who cited Obama, the senator from Illinois who is African-American.
Black men who are registered Democrats were nearly evenly split, with 42 percent favoring Clinton and 46 percent favoring Obama. The sampling error of that question was plus-or-minus 8 points.