In this paper, we analyze the determination of immigration policy in a direct democracy setting. We formulate a model of voting and participation behavior integrating instrumental and expressive motivations. The model is estimated using data drawn from a survey carried out after a vote in Switzer- land in 2000 on a popular initiative proposing to implement immigration re- strictions. The model enables us to recover estimates of participation costs and preferences towards immigration and analyze how these preferences are translated into actual voting outcomes. The results reveal a substantial gap (“participation bias”) between attitudes towards immigration in the general population (43% favorable to restrictions) and the outcome of the vote (26%).