Incumbent Chris Coons defeated three challengers on Tuesday to secure the Democratic nomination for Delaware's US Senate seat. Former state senator Mike Katz won the Republican primary to face Coons in the November general election. Among the Democratic challengers, 2024 Republican nominee Eric Hansen finished last with 3% of the vote.

Progressive candidate Shay Frisby, endorsed by Bernie Sanders and the Democratic Socialists of America, unseated incumbent Raymond Seigfried in State Senate District 5 with 762 votes or 51.4%. Incumbent Franklin Cooke retained his State House District 16 seat with 262 votes or 51.6% against challenger Pamela Salaam. These results finalized Delaware's 2026 primary election cycle.