Five candidates are running in the Democratic primary for the U.S. Senate in New Hampshire on Sept. 8, 2026. Incumbent U.S. Sen. Jeanne Shaheen (D-N.H.) is retiring from public office. Karishma Manzur (D) and Chris Pappas (D) lead in polls, fundraising, and media attention.

According to Spectrum News 1 Worcester's Donovan Lynch, there is an ideological divide between Manzur and Pappas. Lynch described Manzur as a progressive and Pappas as a moderate.

As of Aug. 19, 2026, Pappas has raised $15,384,657, and Manzur has raised $415,081. Lynch wrote that "Even so, progressive Democrats have recently notched primary victories over better-funded establishment candidates in places like Florida, where state Rep. Angie Nixon pulled off a stunning upset over a moderate and former national security official Alex Vindman earlier this month."

Manzur's professional experience includes working as a medical scientist, where she developed treatments for neurological diseases. She also served as a representative on the New Hampshire Democratic Party's Rules Committee. Additionally, Manzur has served on the boards of the nonprofit organizations NH Ranked Choice Voting and Open Democracy.

In her Candidate Connection survey, Manzur wrote, "My commitment to improving people's lives extends beyond the research field and is a major reason I am running for U.S. Senate. As Senator, my priorities will include banning big money in politics, championing Medicare for All, building affordable housing, and pursuing a sensible, humane foreign policy that ends war profiteering."

Peace Action, Southern New Hampshire Indivisible, and Progressive Democrats of America endorsed Manzur.

Pappas was first elected to represent New Hampshire's 1st Congressional District in 2018. He previously served on the New Hampshire Executive Council from 2013 to 2019, as Hillsborough County Treasurer from 2007 to 2011, and in the New Hampshire House of Representatives from 2002 to 2006. Pappas professional experience includes co-owning his family's restaurant.

Pappas said, "Change is about making sure that we can reestablish power for the people of New Hampshire and the people of this country. Flip the majority in the U.S. Senate and go on offense on the things that people care about: building a fair economy, lowering costs, taking on corruption and creating a freer and fairer society for everyone."

Former Vice President Kamala Harris (D), Shaheen, and U.S. Sen. Maggie Hassan (D-N.H.) endorsed Pappas.

David Jarvis (D), Maxwell Saal (D), and John Vail (D) are also running.

As of Sept. 1, 2026, The Cook Political Report and Sabato's Crystal Ball rated the general election as Lean Democratic. Inside Elections rated it as Tilt Democratic. DDHQ/The Hill rated it as Likely Democratic.