The party politics of immigration is one of the fastest growing bodies of research within the study of West European politics. Within this literature, an underlying assumption is that immigration has become one of the most salient issues. However, this is rarely documented, let alone explained. Drawing on a new coding of party manifestos in seven West European countries, this article shows that party attention to immigration has grown in all countries since 1980 but only in Denmark has the issue become one of the most salient issues of party politics. We find that the general increase in attention reflects the rising number of immigrants and rise of radical right-wing parties. In terms of the issue becoming a top issue of party politics, a comparative analysis of the politicization of immigration in Denmark and the Netherlands shows that the interest of mainstream right-wing parties and coalition dynamics are the crucial factors.