The goal of this article is to establish (a) the relationship between electoral lists, party membership, and changes in party affiliation in the context of (b) electoral-list mobility. Our basic premise is that the illegible institutional rules for placing candidates on electoral lists favors mobility between lists. We use data from the EAST PaC Database (2005–2015), which allows us to estimate to what extent the composition of electoral lists differs in terms of the party affiliation of candidates and to track the mobility of parliamentary candidates between electoral lists in consecutive elections. Our basic findings confirm that candidates who changed party affiliation and those who were independent were most likely to change electoral lists. This is a quite surprising finding because according to studies (Shabad and Słomczyński 2002, 2004) such candidates, whose election potential is uncertain, should be unwelcome on new electoral lists.