David Cameron - the first Conservative leader to win an outright majority for 23 years - named his ministerial team.
Sajid Javid took the job of Business Secretary and Boris Johnson was handed a non-ministerial role while he remains Mayor of London.
A number of female MPs, including Priti Patel and Amber Rudd, were also promoted to leading positions.
It is "very difficult" to see how Ed Miliband could be prime minister based on the exit poll, Lord Mandelson has told ITV News.
Asked whether Miliband could still form a government based on the poll numbers, Lord Mandelson told Tom Bradby: "On these numbers, on the exit poll, very difficult indeed."
Mandelson said a defeat for Ed Miliband may not spell the end for his leadership, saying: "He has performed magnificently during this campaign."
He also said "something akin to an earthquake" has happened in Scotland, if exit polls, predicting the SNP will win 58 out of 59 seats, is proved correct.
It was one of the last big Cabinet jobs to be announced but the Prime Minister has chosen to stick with Jeremy Hunt as Health Secretary.
Prime Minister David Cameron has today continued to put together his new cabinet. Here is what the new-look cabinet looks like so far.
David Cameron was unsurprisingly in a great mood as he spoke to journalists before addressing his 331 Conservative MPs today.