In what ways, if at all, does transparency influence how politicians cooperate with interest organizations? While there areconvincing normative arguments stressing the importance of transparency in politics, empirical evidence for how transparencyin practice affects how politicians reason regarding cooperating with interest organizations is scarce. In this article, I addressthis gap by conducting a mixed method survey experiment with 1659 Swedish politicians. The findings indicate that a lack oftransparency, as explored in this study, diminishes politicians' willingness to closely cooperate with interest organizations bysubmitting policy proposals drafted by these organizations. However, the central concern for most politicians, in both thetransparent and untransparent conditions, was whether they had exercised independent political judgment rather than blindlyaccepted the interest organization's suggestion. These results contribute to the literature by showing how a specific form oftransparency influences cooperation between politicians and interest groups, while also offering theoretical insights into thecritical role of political judgment in this cooperation.