バローゾ委員会
Rehn served briefly on the Prodi Commission. He was appointed European Commissioner for Enterprise and Information Society on 12 July 2004, taking over the role from the previous Finnish Commissioner Erkki Liikanen, who left his post the same day to become Governor of the Bank of Finland. The Finnish government nominated Rehn for the incoming Barroso Commission, which took office on 22 November 2004. He was the youngest member of the first Barroso Commission.