Purpose. This article analyzes negative campaigns on social media during presidential elections in seven South American countries. Methodology. Through a content analysis of 15,073 posts on X, Facebook, Instagram, and TikTok, the study investigates the predominant type of message (positive, contrast, or negative), the social network with the highest concentration of negative content, the dimension of these messages (personal or political), and the influence of the candidate's ideology. Results and Conclusions. The results show that the majority of the messages are positive (80%). X turned out to be the platform with the highest presence of negative messages, although these are mainly focused on the political dimension of the candidates. No significant differences were found in the use of negative campaigns between left-wing and right-wing candidates. Original Contribution. In summary, th...