In this article we address two questions considering the Flemish regional elections of June 2009. First we determine whether this campaign can be called a negative campaign and what amount of negativity it contained. Second, we want to know what the consequences of negativity were on voter preferences. Our research, based on a newspaper analysis, shows that the campaign contained an average amount of negative campaign messages compared to campaigns in other political systems (United States, the Netherlands and Denmark). We calculated effects on voter preferences by means of the PartiRep Belgian Voter Survey of 2009, a survey with a unique three wave panel design. The results demonstrate that negative campaigning seems to have been effective in 2009. Parties with negative campaigns attracted more attention from voters and also seemed to gain during the campaign. Personal attacks on opponents, on the other hand, did not have an effect on the electoral appeal of a party. Incumbent parties even lost votes when they launched personal attacks. The results suggest that, in the Flemish context, an attack on the opponent’s program or governmental record can be effective, but that personal attacks are not rewarded by the voters.