European Parliament elections are an important part of the European Union's (EU) democratic accountability since the European Parliament (EP) is the only directly elected institution of the EU. An important question thus is: What explains citizens' voting behavior in EP elections? The existing literature describes EP elections as largely second-order elections that are mainly decided on national rather than European issues. However, the recent immigration crisis has brought European-level policymaking to the forefront of public attention across the EU. The overall goal of our paper is thus to determine whether the issue of immigration turned the 2019 EP elections into elections about European rather than national issues. Our specific research goals are: To determine 1) whether and how immigration attitudes influenced voters' preferences in the 2019 EP elections; and 2) whether and how the importance of immigration changed throughout the campaign. In answering these questions, we focus on Germany, where the immigration crisis has been a key political issue. In contrast to the existing largely cross-sectional literature, our analysis makes use of a three-wave panel design (two pre-election and one post-election wave) incorporated in the probabilistic mixed-mode GESIS Panel. This allows us to study voting preferences in a dynamic view, enabling us to make confident conclusions about causality. The results have implications for democratic accountability in the EU.