A new University of New Hampshire poll suggests incumbent Sen. Ed Markey’s lead over Rep. Seth Moulton has narrowed ahead of September’s Democratic primary.

Markey and Moulton are competing in the Democratic primary for Massachusetts’ U.S. Senate seat ahead of the 2026 midterm elections.  Moulton has called for a “new generation of leaders who listen more to the people that we represent and honestly represent their needs and concerns,” while Markey has said his bid is “about the people” and “powered by grassroots supporters from every corner of our Commonwealth.”

The University of New Hampshire survey was conducted June 18-23 among 623 likely general election voters.

“Markey and Moulton are both favored in general election matchups with presumptive Republican Senate nominee John Deaton,” the Bay State Poll read. “Incumbent Sen Ed Markey continues to lead Rep. Seth Moulton in the Democratic primary for U.S. Senate in Massachusetts, but his lead has narrowed.”

Among likely Democratic primary voters, 41% said they support Markey, while 35% back Moulton. An additional 24% are still undecided, and 1% would vote for another candidate.

“The momentum on the ground is undeniable, and this poll proves what we’ve been hearing in every single town: Massachusetts voters are completely sick of the same old, tired Washington politics,” said Taylor Hebble, campaign spokesperson for Moulton’s campaign.

Markey’s campaign did not respond for comment.

Markey’s support has fallen from 46% in April. Undecided voters have increased in the last two months as well, rising from 15%.

Moulton leads among moderates, with 70% support, while slim majorities of liberals (51%) and progressives (52%) back Markey. Markey also holds a 67% advantage among self-identified socialists.

Markey’s overall net favorability rating (the percentage of those who have a favorable rating minus those who are unfavorable) among Democratic primary voters fell to +30 from +42 in April.

Moulton’s net favorability also declined, dropping from +24 in April to +11.

Polling from May similarly found Markey holding a five-point lead over Moulton. The Emerson College Polling found Markey leading 37% to 32%, with 29% of voters undecided.

An April 15 poll by the Suffolk University Political Research Center and the Boston Globe showed 79-year-old incumbent Markey at 47%, while 47-year-old Iraq War veteran Moulton had edged up to 30.4%.

The primary is September 1, with early voting starting August 22.