Incumbent Ed Markey and Seth Moulton are running in the Democratic primary for U.S. Senate in Massachusetts on September 1, 2026.

This is one of several primaries this year in which age has become an issue. Markey is 80, and Moulton is 47. Markey is running on his record, while Moulton has said he would be part of a new generation of leadership.

Markey said, "I'm more energized than I've ever been before. I am crisscrossing the state. I am fighting for families. It brings out the Malden in me every single day, seeing what Trump is doing to families. Congressman Moulton has a hard time keeping up with me in the course of this campaign. So for me, if somebody can't do the job, they should just step down. But I can do the job."

Moulton said, "We should have age limits for Congress, just like we have age limits for Massachusetts judges. Now I don't know exactly what the answer is, but I've made three promises. (1) to foster the debate (2) to fight hard to get whatever the conclusion is passed into law, and (3) if I'm ever in that position to abide by it myself regardless if it gets passed. I've served with some of the most amazing leaders in my life in the Marines but at 23 years old they don't get to run for Congress. I think we should have upper age limits as well.”

Markey first took office in 2013. Before serving in the Senate, he represented Massachusetts' 5th Congressional District from 1976 to 2012 and served in the Massachusetts House of Representatives, representing the 26th Middlesex District and the 16th Middlesex District from 1973 to 1977. Markey's other experience includes serving in the U.S. Army Reserve from 1968 to 1973 and working as a lawyer. His campaign website says, "Throughout his career, Ed has refused to compromise his progressive values in his fight to build a Commonwealth and country that are fair, just, and equitable for all." Markey's campaign website says he supports advancing a national Medicare for All program, universal early learning programs, tuition-free community college, and efforts to codify a Transgender Bill of Rights. U.S. Sen. Bernie Sanders (I-Vt.), U.S. Sen. Elizabeth Warren (D-Mass.), U.S. Rep. Alexandria Ocasio-Cortez (D-N.Y.), and U.S. Rep. Ayanna Pressley (D-Mass.) endorsed Markey.

Moulton represents Massachusetts' 6th Congressional District. He first took office in 2015. Before his time in Congress, Moulton served in the Marine Corps, serving four tours in Iraq between 2002 and 2008. From 2011 to 2013, Moulton worked as managing director of Texas Central Railway. Moulton's other experience includes being the co-founder and president of the healthcare company Eastern Healthcare Partners. Moulton, who is running on his record in Congress and military experience, completed Ballotpedia's Candidate Connection survey. In his response, he wrote, "I’ve always stood up to the status quo to fight for progressive values...I won’t vote for Chuck Schumer for leadership. I’m taking on Trump and corporate greed with the most progressive affordability agenda in this race, treating housing, healthcare, and education as human rights." Moulton is running on his military experience and his record in Congress. In his survey, he also said he supports implementing universal pre-K, lowering prescription drug prices, and passing Universal Healthcare. New Jersey Gov. Mikie Sherrill (D), U.S. Rep. Derek Tran (D-Calif.), U.S. Rep. Chrissy Houlahan (D-Pa.), and the Boston Globe endorsed Moulton.

Thirty-three of the 100 U.S. Senate seats are up for election, and another two seats are up for special election. Democrats hold 13 of the seats up for election, and Republicans hold 22. As of April 2026, 11 members of the U.S. Senate announced they are not running for re-election. To read more about the U.S. Senate elections taking place this year, click here.