Bulgaria's Kristiyan Vigenin was elected deputy floor leader of the Socialist group in the European parliament (PES), the group said on its website.
Vigenin headed the Socialist ballot in Bulgaria's first ever MEP vote last month and becomes the eighth vice-president on the PES executive body.
Vigenin was appointed following a secret vote, which he won with a comfortable majority.
His appointment confirms the influence Bulgarian Socialists have with their European colleagues, as he is the only MEP from newly-acceded countries to get a VP seat in the PSE bureau.