In the European Parliament, Wortmann-Kool served on the Economic and Monetary Affairs Committee (ECON), the Transport and Tourism Committee (TRAN) and the Committee for Women's Rights and Gender Equality (FEMM). Furthermore, she was a member of the parliamentary delegation for the United States and the parliamentary delegation for the Caucasus. Until 2009, Wortmann-Kool was the Vice-Chair of the Committee on International Trade and rapporteur for trade relations between the EU and China. She represented the Parliament at the 2009 United Nations Climate Change Conference in Copenhagen.