Does direct democracy increase political participation? How? Rather than focus on state-level effects of the initiative process, this paper studies the direct effect of signature gathering campaigns on participation within a state. We test whether parts of the state that are subject to more intense signature gathering campaigns, measured by the number of signatures gathered per capita, experience greater levels of political participation. We examine three measures of participation: registration, turnout, and ballot rolloff. Our key variable is the intensity of the signature gathering campaign across eight specific ballot measures or across measures for four specific elections. Grouped logit analysis demonstrates that the intensity of signature gathering campaigns is strongly related to these measures of political participation. In addition, we also study how signature gathering intensity influences vote choice on associated measures, finding that on average increased signature gathering intensity increases support for a measure.