In contrast to beliefs in specific conspiracy theories, conspiratorial predispositions refer to people's propensity to view the world in conspiratorial terms. As such, they are one of the most important antecedents of beliefs in specific conspiracy theories. Understanding the antecedents of conspiratorial predispositions is hence important. Despite this, there is still only limited research on the antecedents of conspiratorial predispositions. Previous research has also not taken the role of media use into account, even though media constitute the most important source of politically and societally information. To remedy this, in the current study we use a large-scale panel study in Sweden to investigate the antecedents of conspiratorial predispositions, with a particular focus on the role of media use. Among other things, the results show that use of right-wing political alternative media is one of the most important antecedents of conspiratorial predispositions, even when accounting for ideological leaning and ideological extremity.