Trump is leading with 46% of likely voters, while Clinton has 45%. The two candidates are divided by a slim .7 percentage point margin, which is well within the poll's margin of error.
Trump led Clinton in just one other ABC News/Washington Post tracking poll, conducted in May shortly after he clinched the Republican nomination. At the time, Clinton and former Democratic candidate Bernie Sanders were still locked in a primary battle.
The poll—conducted between Oct. 27 and Oct. 30—surveyed 1,128 likely voters and had a margin of sampling error of plus or minus 3 percentage points.
The RealClear Politics polling average for Oct. 22 to Oct. 31 shows Clinton ahead by a margin of 2.4 percentage points with 47.7% support.