This paper focuses on the policy strategies adopted by social democratic parties and their impact on the class basis of their support. It is argued that political appeals matter for explaining the development of class voting. This argument is tested through a comparison of the policy strategies of social democratic parties in Austria and Switzerland and the evolving patterns of class voting in the two countries. Using election surveys and data on the policy positions and media representation of the political parties from the 1970s to the 2000s, the article finds that the Social Democratic Party in Austria maintained a strong working class base. In contrast, the Social Democratic Party in Switzerland facilitated a major transformation of the class basis of its support by emphasising new cultural issues. It became the party of the ‘new middle classes', leaving the working class to realign in support of the Swiss People's Party.