Despite a fast-growing body of literature on fake news and mis-/disinformation, there remains surprisingly little empirical work on the social/political consequences of exposure to false information. Addressing this issue, this study provides initial evidence that perceptions of false information exposure catalyze political cynicism. The findings from a two-wave panel survey during the 2018 US midterm elections reveal that perceptions of false information exposure 2 weeks before the election significantly predict the changes in political cynicism immediately after the election day. We also find that social media news use in Wave 1 significantly relates to political cynicism in Wave 2 indirectly through perceptions of mis-/disinformation exposure. The autoregressive regression model indicates that our findings are robust after controlling for prior levels of cynicism.