The Quinnipiac University poll released Wednesday shows both men at 43 percent.
It is the Connecticut school's first post-primary survey in the race. The numbers changed little since Quinnipiac released a May 13 poll that showed Toomey with 42 percent to Sestak's 40 percent.
In the new poll, just 12 percent say they're undecided. Independent voters in the poll favor Toomey, 44 percent to 35 percent.
The telephone poll of 1,367 Pennsylvania voters was conducted during the six days that ended Sunday. The sampling error margin is plus or minus 2.7 percentage points.
The election is Nov. 2.
