Toomey leads McGinty, a former member of the Bill Clinton administration, by four points, 49-45, among likely Pennsylvania voters.
The incumbent senator's lead has narrowed since Quinnipiac last polled the U.S. Senate election in Pennsylvania in September. Toomey led +8 in September, and now the poll favors Toomey +4.
The Quinnipiac University poll was conducted Oct. 10-16 via live telephone interview among 660 likely Pennsylvania voters, and has a margin of error of plus or minus 3.8 percent.
TPM's PollTracker Average for the U.S. Senate election in Pennsylvania shows Toomey leading McGinty, 46.6 to 44.4.