The city mailed sample ballots out this week to remind registered voters of the primary election coming up on Sept. 13.
Trouble is, the forms are telling them to go to the polls Sept. 3.
The city's elections director blamed a private printing company for the incorrect date, which appears in one place on the 2011 Official Primary Sample Ballot, which was sent to nearly all of the city's more than 360,000 registered voters. The correct date appears elsewhere in the mailing.
Elections director Armstead B.C. Jones Sr. was looking for the bright side Wednesday.
"The 3rd is an early-voting day," he said. "One good thing is that it wasn't a date after the election."
Polls will open at all 290 of the city's precincts on Sept. 13. Early voting will be limited to five sites Sept. 1-8.
Jones said the elections board learned of the mistake Tuesday, when voters started calling.
"It was reviewed and signed off on," said Jones of the sample ballot. "It went through several hands."
Jones said the board would mail postcards early next week explaining the error. The printer that made the mistake will pay for the postcards, he said, and the city will pay for postage.
Jones could not say how much it would cost. The Board of Elections sends its mailings at a first-class bulk rate through the U.S. Postal Service.
"Cost is not a factor with a situation like this," he said.
He said the board would also put up posters in all of the precincts before Sept. 3 noting the error and directing voters to one of the five early-voting sites.
Those sites are Edmondson Westside High School, 501 Athol Ave.; The League for People with Disabilities, 1111 E. Cold Spring Lane; Moravia Park Drive Apartments, 6050 Moravia Park Drive; the Public Safety Training Center, 3500 W. Northern Parkway; and St. Brigid's Parish Center, 900 S. East Ave.
The board put a brief note up on its website Wednesday afternoon apologizing for the error.
Jones said only a few voters had noticed the error and called his office.
"Phones have not been ringing off the hook," he said.
In 2000, between 25 and 50 Howard County voters received the wrong sample ballots because of an error by the printer. Some Democrats received ballots intended for Republicans in that election.
Mayor Stephanie Rawlings-Blake is running to keep her post against a crowded Democratic field in the upcoming primary.
Her challengers include Clerk of Courts Frank M. Conaway Sr., former Greater Baltimore Board of Realtors head Joseph T. "Jody" Landers, state Sen. Catherine E. Pugh, former city planning director Otis Rolley and nurse Wilton Wilson.
Rawlings-Blake, who succeeded Sheila Dixon as mayor in February 2010, has raised more than $1.4 million in donations this year from more than 1,000 people, according to her campaign.
The sum is more than all of her opponents combined, and Rawlings-Blake has also secured the endorsements of many important political figures throughout the city and state.
Baltimore Sun reporters Julie Scharper and Justin Fenton contributed to this article.