Five candidates are running in the Democratic primary for Missouri's 1st Congressional District on Aug. 4, 2026. Incumbent Rep. Wesley Bell (D) and Cori Bush (D) lead in noteworthy endorsements and fundraising.

As of June 2026, this primary is one of five in the 2026 election cycle in which a former member of the U.S. House of Representatives is running against an incumbent member. Bush represented Missouri's 1st Congressional District from 2019 to 2025. In 2024, Bell defeated Bush 51.1% to 45.6% in a field of four candidates.

During the 2024 primary, the American Israel Public Affairs Committee's (AIPAC) affiliate, the United Democracy Project (UDP), spent $9.3 million either against Bush or in support of Bell. The Cook Political Report's Matthew Klein wrote that "As the Democratic electorate grows increasingly angry over the war in Gaza and AIPAC's meddling in primaries across the country, Bush is counting on an anti-Israel backlash to put her over the top." According to Politico's Cheyanne M. Daniels, the organization has not spent in this year's primary, but they did endorse Bell.

On AIPAC's involvement in elections, Bush said, "The tide has already turned, and people are saying no. They want to be the ones to pick their representatives. And so, whether that money filters into the community or not, I think the community is also going to call out any candidate who is accepting that money."

Bell said the organization's involvement in the 2024 primary would not affect the 2026 primary: "Voters in our district are worried about the cost of living. They're worried about health care costs. If you don't have anything to run on, well, you got to create something. And that's what other folks in the race are doing."

Before serving in the U.S. House, Bell served as the St. Louis County Prosecuting Attorney from 2019 to 2025, and on the Ferguson City Council from 2015 to 2018. He also worked as a lawyer.

According to Bell's campaign website, he is running on "holding the Trump administration and MAGA Republicans accountable, expanding access to affordable health care and prescription drugs, lowering energy costs, bringing down the price of groceries, protecting our rights and freedoms, and creating good-paying jobs right here in St. Louis." Democratic Leader Rep. Hakeem Jeffries (D-N.Y.), Democratic Whip Rep. Katherine Clark (D-Mass.), and the Congressional Black Caucus PAC endorsed Bell.

Before serving in the U.S. House, Bush worked as a pastor and a registered nurse. She was also the co-director of The Truth Telling Project, which, according to its official website, "works to help people understand the deep-seated institutional racism that allows for police violence to occur and the pervasive impact that violence has on families and their communities."

According to Bush's campaign website, she will "fight on behalf of St. Louis by focusing on securing historic funding for our community, lowering costs, and building an economy that works for all of us."  U.S. Sen. Bernie Sanders (I-Vt.), Our Revolution, and St. Louis Democratic Socialists of America endorsed Bush.

As of June 23, 2026, The Cook Political Report with Amy Walter and Inside Elections with Nathan L. Gonzales rated the general election as Solid Democratic. Larry J. Sabato's Crystal Ball rated it as Safe Democratic.

Carl Harris Sr. (D), Carl Henderson (D), and Alissa Murphy (D) are also running in the primary.