The selection of the parliamentary elite is a topic only partially analyzed. Most of the work in the field studies the parties’ written rules regarding the selection of candidates in the national chamber(s). However, the party statutes do not provide information about the informal mechanisms behind these formal procedures. Do party rules reflect the real practices in candidate selection? Are these procedures different in regional and in national chambers? In this paper we analyze how the selection of the parliamentary elite takes place using survey data with a representative sample of 580 Spanish MPs completed with 58 in-depth interviews. Thanks to this data, we can analyze how the selection of candidates is implemented in a multi-level democracy such as Spain.