Venizelos was elected as a PASOK MP in the Thessaloniki A constituency in the general elections of 1993, 1996, 2000, 2004, 2007 and 2009. He has been a member of the parliamentary committee for the Revision of the Constitution, on which he was spokesman for the majority party in the parliaments elected in 1993, 1996, 2000, 2004 and 2007. He was also a member of the Standing Committees on National Defence and Foreign Affairs, on Public Administration, Public Order and Justice and on European Affairs.