In June 2004, Osborne was selected as the Labour candidate for the new constituency of Ayr, Carrick and Cumnock, where she was returned at the 2005 general election with a majority of 9,997 votes. She served on the Foreign Affairs Select Committee from 2005 to 2010. She is also Secretary of the All Party Group on Colombia and the Women, Peace and Security Group. In 2006, then-Prime Minister Tony Blair appointed her as a member of the UK Delegation to the Parliamentary Assembly of the Organization for Security and Co-operation in Europe (OSCE).