Clinton comes out ahead, 46-40, in Wisconsin, with Libertarian Gary Johnson polling at 4 percent and Green Party candidate Jill Stein at 3 percent.
The six-point lead for Clinton comes as Donald Trump is making last-minute efforts to campaign in the Badger State.
Clinton's lead decreased slightly since Marquette last polled in early October. In a head-to-head match she led by four points, 46-42, while she led by seven points, 44-37, when third-party candidates are included.
Today's Marquette poll did not ask about head-to-head presidential preference between Clinton and Trump.
The Marquette University poll was conducted Oct. 26-31 among 1,255 likely Wisconsin voters via live telephone interview, with a margin of error of plus or minus 3.5 percent.
TPM's PollTracker Average for the general election in Wisconsin shows Clinton leading Trump, 46.2 to 42.2.