The Bundesrat is the constitutional body in Germany, which ensures the participation of federal states’ governments in legislative and administrative affairs at national and European Union (EU) level. Hence, it is political in nature, since these governments are comprised of parties and politicians. Yet, experts of federal states’ administrations dominate the committees that prepare the (political) decisions in the plenary sessions in substance and great detail. Early on, scholars thus called into question whether politicians or technocrats drive Bundesrat decision-making. The literature largely follows the assumption that (party) politics is almost absent from the committees, but there is a crucial lack of empirical data. We scrutinise the presumed dominance of technocracy over politics in the committees. A new data set allows us to analyse the voting behaviour of the federal states and the respective governing parties in the Bundesrat committees since 1991. Currently, the data sets contains almost 30.000 votes that provide a large-scale empirical basis for specifying party-influenced votes. The paper begins with pointing out the tensions between technocratic norms and political interests that are inherent to the Bundesrat committees. Eventually, it presents empirical evidence on the extent to which party-influenced votes dominate committee decisions. We focus on votes related to two specific procedures that together add up to the majority of committee work: the submission of opinions on draft government bills and on EU policy (proposals). The data reveal that party politics is not absent from the committee work. More specifically, our findings present two decisive facets of party-influenced votes. First, their overall share is considerably higher for opinions on draft government bills compared to those on EU policy, meaning there is a higher degree of partisan conflict over domestic than European issues. Second, there are ‘political’ and ‘non-political’ committees what hints at different committee cultures.