In comparison with Tony Blair's last Cabinet, Brown retained seventeen ministers including himself.
Alistair Darling replaced Brown as Chancellor of the Exchequer while his portfolio at Trade and Industry was renamed Business, Enterprise and Regulatory Reform and given to John Hutton. Hutton was in turn replaced as Work Secretary by Peter Hain, who continued as Wales Secretary but not as Northern Ireland Secretary, a post that went to Shaun Woodward.
David Miliband was promoted from Environment Secretary to Foreign Secretary and was replaced in that brief by Hilary Benn, then International Development Secretary. Douglas Alexander filled Benn's seat whilst his posts as Transport and Scotland Secretaries were given to Ruth Kelly and Des Browne, respectively, the latter of whom stayed on as Defence Secretary. Jack Straw became the first MP Justice Secretary and Lord Chancellor, declaring it a new Great Office of State. Amid speculation that Brown would appoint him as deputy prime minister and/or First Secretary of State, neither title was conferred on any member. The other name that cropped up for the two roles was the new Labour Party Chair and Deputy Leader, Harriet Harman, who made a return to Cabinet after nine years as Leader of the House of Commons and Lord Privy Seal and was given the additional brief of Minister for Women and Equality. It was believed that the Government Equalities Office would become its own department headed by an Equalities Secretary; however, it was not given Secretary of State status. The previous home of the Equalities Office and of Ruth Kelly was the Communities Secretary, a post which was given to Hazel Blears, whose previous role as Minister without Portfolio was not given due to Harman's (the new party chair) full inclusion in Cabinet. Harman's strongest competitor for the deputy leadership, Alan Johnson, became the Health Secretary while his previous role as Education Secretary was split into a Schools Secretary and a Universities Secretary and respectively given to Ed Balls and John Denham.
Former Commons Chief Whip Jacqui Smith was given a substantial promotion as the first female Home Secretary and was replaced by Geoff Hoon, who was promoted from being the Europe Minister. His successor, Jim Murphy, was not given a provision to attend Cabinet as he was.