Clinton leads Trump by 3 points, 43 percent to 40 percent, in a head-to-head match-up in the Morning Consult poll released Sunday morning.
One week ago, Clinton led Trump by 6 points, 44 percent to 38 percent.
Voters view both candidates unfavorably, pollsters found, with 58 percent holding a negative view of Trump and 57 percent saying the same about Clinton.
Clinton has the support of 79 percent of African-Americans, compared to 5 percent of black voters who back Trump.
Trump also trails Clinton among women, 44 percent to 35 percent.
The new poll of 2,007 registered voters, conducted Aug. 24–26, has a margin of error of 2 percentage points.