Theresa May has won the first round of the contest to become the next Tory leader and PM and says she is the only candidate left who can unite the party.
The home secretary got 165 of 329 votes cast by Tory MPs. Andrea Leadsom came second with 66 and Michael Gove got 48.
Liam Fox was eliminated in fifth place. Stephen Crabb came fourth and dropped out. Both have since backed Mrs May.
Further voting will narrow the field to two. The eventual outcome, decided by party members, is due on 9 September.
Following the result, Mr Gove, the justice secretary and a leading Leave campaigner, insisted he would stay in the race, saying the winner should be someone who backed Brexit.
Mrs Leadsom, an energy minister, was also a key figure in the campaign to leave the EU, appearing alongside Boris Johnson in some of the TV debates.
The leadership contest was sparked by David Cameron's decision to step down as prime minster after the UK voted by 52% to 48% to leave the EU, in the 23 June referendum.
The prime minister, who had campaigned strongly for a Remain victory, said "fresh leadership" was required as the UK negotiates its exit from the European Union.
The process of choosing a successor - and the new prime minister - began on Tuesday, as 329 of the 330 Conservative MPs took part in a secret ballot between 11:00 and 18:00 BST.
The result was announced half an hour later by Graham Brady, the chairman of the 1922 committee of backbench Tory MPs, with front-runner Mrs May securing a comfortable lead over her rivals.
- Home Secretary Theresa May - 165 (50%)
- Energy minister Andrea Leadsom - 66 (20%)
- Justice Secretary Michael Gove - 48 (15%)
- Work and Pensions Secretary Stephen Crabb - 34 (10%)
- Former Defence Secretary Liam Fox - 16 (5%)
Mrs May - who has said she will deliver Brexit if PM - said she was "pleased" with the result and "grateful" to colleagues for their support.
She said there was a "big job" ahead to unite the party and the country following the referendum, to "negotiate the best possible deal as we leave the EU" and to "make Britain work for everyone".
She added: "I am the only candidate capable of delivering these three things as prime minister, and tonight it is clear that I am also the only one capable of drawing support from the whole of the Conservative Party."
Mrs May has published her tax returns for the last four financial years, meaning her closest rival after the first round Mrs Leadsom is now the only leadership candidate not to have done the same.
Mrs May's statement from the private bank Coutts showed she paid £40,023 in income tax in 2014/15 and earned £112,426 from her MP and home secretary salaries and a further £6,036 in interest and dividends.
Mr Fox - who came third in the 2005 contest which Mr Cameron won - said he was "disappointed" to be knocked out, but did not regret standing.
Mr Fox - who has previously said the new leader must be a Brexit supporter, given the result of the referendum - announced he would now be backing, and campaigning for, Mrs May.
He said it was essential that the new leader, given that they will also be prime minister in a matter of weeks, has an understanding "at the top levels of government and of international affairs" and knows how the Whitehall process works.
Mr Crabb - formerly Welsh secretary before his promotion to work and pensions secretary - opted to voluntarily withdraw from the race on Tuesday evening.
He said the result of the vote showed Mrs May was the "only candidate" able to unite the party and to form "a cohesive and strong government" - and pledged his support for her candidacy.
Mr Crabb also said that the quicker a new leader and prime minister was in place "the better", given the "seriousness of the situation facing the country".
Mr Gove said he was "delighted" by the support he had received, saying it reflected his "optimistic message" about Britain's future outside the EU.
"I think the country deserves to have a leader who believes in Britain outside the European Union and who also has experience at the highest level of government," he said, adding that he would be seeking to shore up support to try to get on the final ballot.
Northern Ireland Secretary Theresa Villiers, who is backing Mrs Leadsom - who also counts Boris Johnson among her backers - said it was "a good result" for her candidate.
"I think we've had a clear steer so far that Theresa (May) and Andrea (Leadsom) are the best people to go forward to the membership," Ms Villiers added.
The three remaining contenders are due to face a second MPs' vote on Thursday to whittle the field down to two names, who will then go forward to a vote of the entire Conservative membership.