Opposition in autocracies often uses negativism against the regime to frame its principal message. This study is the first to experimentally evaluate the effectiveness of a negative campaign on a regime candidate’s vote share. For the field experiment conducted during the 2013 Moscow mayoral election, we published a newspaper criticizing the incumbent mayor. We distributed approximately 130,000 copies near the entrances of 20 stations on four randomly selected metro lines one month prior to the election. We found that the incumbent’s vote share was 1.7 percentage points lower at the voting stations where the newspaper was distributed. These votes go to other candidates who address issues raised by the negative campaign. Anti-regime campaigning does not suppress turnout or increase disapproval voting.