The primary will extend a nasty fight between Paladino, a proudly politically incorrect novice aligned with the tea party movement, and Lazio, a former congressman from Long Island.
The deadline to contest thousands of signatures on Paladino's petition to get on the Sept. 14 ballot expired at midnight Monday.
State Board of Elections spokesman John Conklin said Tuesday that no objection to the petition has been filed.
Although an objection would be valid if postmarked Monday, an aide with the Lazio campaign said no challenge was made. The official spoke to The Associated Press on the condition of anonymity because the aide wasn't authorized to comment.
"It's all over," Paladino said of Lazio's chance of avoiding a primary. "They're done." Paladino's supporters collected nearly twice the number of signatures of Republican voters that were required. He had to collect at least 15,000 signatures, including 5 percent of voters in each of at least 15 of New York's 29 congressional districts.