Nearly 150,000 California Mail Ballots Rejected In Primary

California election officials are reviewing why nearly 150,000 mail-in ballots were rejected during the state’s June primary, with late postmarks responsible for the majority of disqualified votes.

Data compiled by the California Secretary of State’s office shows that 148,241 mail ballots were rejected, representing 1.73% of all returned ballots.

That was an increase from the 2024 primary, when 108,982 mail ballots—or 1.56% of those returned—were rejected.

The most common problem involved ballots that failed to meet California’s deadline requirements. State records show that 93,479 ballots were rejected for arriving too late or carrying an invalid postmark.

California accepts mail ballots for up to seven days after Election Day, but only when they are postmarked on or before Election Day. Election specialists believe many of the rejected ballots arrived during the grace period but were postmarked after the legal deadline.

Kim Alexander, president of the nonpartisan California Voter Foundation, said the issue appears to center more on postmark timing than actual delivery.

“Ballots rejected due to lateness are caused primarily to being postmarked too late to count, not because they arrived too late to count,” Alexander said.

The increase has raised questions about whether changes within the U.S. Postal Service are affecting election mail.

Under updated procedures, a postmark may reflect when an envelope reaches a regional processing facility rather than when a voter initially places it into the mail system. With some processing operations consolidated, ballots deposited close to Election Day may not receive a qualifying postmark until later.

A group of mostly Democratic senators warned the Postal Service earlier this year that operational changes could interfere with the timely handling of election materials.

California officials also encouraged residents to send their ballots early ahead of the June primary because of concerns about potential postal delays.

The state’s competitive gubernatorial primary may have contributed to the problem by encouraging voters to wait until the final days of the campaign before making their selections.

Signature problems accounted for most of the remaining rejections.

Approximately 44,000 ballots were disqualified after officials determined that the signature on the return envelope did not match the voter’s signature on file. Another 8,300 envelopes were returned without any signature.

State records also show that 743 ballots were rejected because the voter had already submitted another ballot.

Other problems included voters returning empty envelopes or placing multiple ballots inside a single envelope.

Tulare County recorded California’s highest rejection rate, with 3.52% of returned mail ballots disqualified. Alpine and Merced counties followed at 3.36% each.

California has long faced criticism over the amount of time required to complete its election counts. Because qualifying mail ballots may arrive for days after Election Day, final results in competitive races can take weeks to certify.

President Donald Trump renewed his criticism of California’s election system following the primary, while the Justice Department opened an investigation into election administration in Los Angeles County.

Election specialists caution that the rise in rejected ballots does not, by itself, prove widespread fraud.

A 2025 Brookings Institution report estimated that documented mail-ballot fraud occurred at a rate of approximately four cases for every 10 million ballots cast.

California officials have not reported evidence of widespread fraud connected to the June primary.

Still, the rejection of more than 148,000 ballots will likely intensify scrutiny of California’s election procedures, Postal Service operations and the reliability of a voting system that depends heavily on ballots traveling through the mail.

For voters, the lesson is clear: Waiting until Election Day to mail a ballot creates a real risk that a legally cast vote will never be counted.