Do poll-worker markings disqualify your ballot? No.
Verdict up front: No. A poll worker's mark does not disqualify your ballot. In several US states, election law requires poll workers to write on ballots.
The claim going around this week (#Election2026 #FactCheck) warns that any poll-worker writing voids your vote. The North Carolina State Board of Elections, 14 Oct 2026: “Election workers write on ballots for different reasons as required by law. This in no way affects whether your ballot will be counted.”
Illinois, County clerks and the state board, same day: “Under Illinois law, election judges must initial ballots before issuing them to voters. These initials are an important safeguard and will NOT disqualify your ballot.”
The real rule points at the voter, not the poll worker: a mark that identifies whose ballot it is can get a ballot rejected. A poll worker's administrative mark, including a printed number or a precinct name, does not.
Full brief, with every source and the limits I could not close: https://telegra.ph/Do-poll-worker-markings-disqualify-your-ballot-10-18