Mason-Dixon Polling & Research Inc. surveyed 400 likely Democratic voters Monday and found that Hagan, a five-term state senator from Guilford County, holds a 42 to 17 percent lead over Chapel Hill investment banker Jim Neal. The poll has a margin of error of 4 percentage points.
The other three candidates in the race – Marcus Williams, Duskin Lassiter and Howard Staley – all scored in the single digits in the poll. One in three voters voters remain undecided.
The winner of the primary will likely face Republican U.S. Sen. Elizabeth Dole in November.
Hagan's favorable rating among voters is about twice that of Neal, according to the poll. But almost half of the respondents said they didn't recognize Neal's name, compared with 27 percent for Hagan.
Both candidates hold similar views on issues ranging from the Iraq War to rising gas prices to illegal immigration.
"I believe the war was a mistake," Neal said. "(We should) bring our kids home safely and quickly."
"We've got to end the war. We're spending $11 billion a month on this war," Hagan said.
Hagan and Neal both said the tax cuts championed by President George W. Bush need to be repealed for wealthy individuals. They also said they would try to help people cope with the uncertain economy.
Frustration with immigration is a common complaint from North Carolina voters, they said.
"We've got to follow the law and find a way for people to legally come into our country ," Hagan said.
"We do need to strengthen our ports of entry, but we also need to provide a pathway to citizenship for people making a living here who are part of the economy," Neal said.