This study investigates media effects on stereotypic attitudes toward immigrants in a political campaign that dealt with the naturalization of immigrants. By combining a content analysis of the campaign coverage with a 2-wave panel survey, the study found that negative news portrayals of immigrants increased stereotypic attitudes in the public in the course of the campaign. Additionally, the frequent exposure to positive news portrayals of immigrants reduced the activation of negative outgroup attitudes. However, these findings are contingent on people's issue-specific knowledge. Only people with low to moderate knowledge were influenced by negative and positive news stories about immigrants in the campaign. Well-informed people were resistant to the effects of positive and news portrayals of immigrants.