Prime Minister Theresa May says her government will reduce net immigration to below 100,000 if it wins Britain's June 8 election, reaffirming a promise the Conservatives have made and broken since 2010.
The promise is in the Conservatives' election platform, published on Thursday.
Many Britons who voted last year to leave the European Union were motivated by a desire to control immigration, which has soared as the EU has expanded. EU citizens have the right to live and work in other member states.
Net migration to Britain was 273,000 in the year to September.
The Conservatives give no date to reach the goal.
After Brexit, Britain will have more power to limit those moving to the country. But many economists say the "tens of thousands" target is arbitrary and economically damaging.
The Conservatives' manifesto also said the government may be willing to make a "reasonable" contribution to the European Union after Brexit.
The flagship document also pledges to come to a "fair settlement" for the EU exit bill - but warns Brussels that the days of Britain "making vast annual contributions to the European Union will end".
The manifesto confirms that a Tory Brexit would take Britain out of the European single market and customs unions.
May said there would be dire consequences for Britain if it failed to get a good Brexit deal.
"Make no mistake, the central challenge we face is negotiating the best deal for Britain in Europe," she said.
"If we fail, the consequences for Britain and for the economic security of ordinary working people will be dire. If we succeed, the opportunities ahead of us are great."
The Conservatives pledged to secure the rights of EU citizens living in the UK and British expats in Europe, as well as confirming Britain will remain part of the European Convention of Human Rights for the next parliament.
It also rules out a Scottish independence referendum until after Brexit is complete and aims to maintain "as frictionless a border as possible" between Northern Ireland and the Republic of Ireland.
