Although the role of political parties in structuring vote choice has become considerably weaker in the last 30 years, we find that parties continue to be active organizations and contact one-fifth to one-quarter of the electorate, an activity that has important consequences. Specifically, when contacted by the parties, individuals have a greater propensity to vote and to engage in other political activities. We also find that each of the two major parties has the capability of mobilizing the electorate even when it is not the incumbent party. Even when placed alongside a plethora of control variables, these findings hold up. We conclude that citizen contacting is a method by which party organizations effectively reduce the transaction costs associated with political participation and that it is an important and largely neglected element in most analyses of political behavior.