David Cameron said leaving the EU would threaten Britain's "economic and national security".
The Prime Minister said Britain's new deal offered the "best of both worlds", while leaving the EU would be a "leap in the dark".
Cameron; individual cabinet ministers can campaign as they wish in a personal capacity.
Cameron; Leaving Europe would threaten our economic and national security.
The EU referendum will be "one of the biggest decisions this country will face in our lifetimes", David Cameron has said.
Following a Cabinet meeting, the Prime Minister said the Government position would be to remain in a reformed EU.
He said Cabinet ministers would be free to campaign on either side of the debate and that there would be "many passionate arguments".
"We are approaching one of the biggest decisions this country will face in our lifetimes," Mr Cameron said outside Number 10. "The choice goes to the heart of the kind of country we want to be and the future we want for our children.
"The choice is in your hands, but my recommendation is clear: I believe that Britain will be safer, stronger and better off in a reformed European Union."
David Cameron has announced that the EU referendum will take place on Thursday 23 June.
The Prime Minister is to announce the planned date for an EU referendum following a Cabinet meeting to be held later this morning.
David Cameron is due to outline the details of his EU reform deal to Cabinet members at 10am as he vowed to campaign "heart and soul" to keep the UK in Europe.
The announcement follows 30 hours of negotiations with EU leaders to agree a package of reforms giving Britain "special status".
The Cabinet will this morning discuss the UK's new special status in the EU - afterwards I'll announce the planned referendum date.
The Prime Minister is urging Oxfordshire County Council to look again at its proposals for £69m of cuts. He says he understands that councils must make further savings but, as an Oxfordshire MP, he says the council should have a re-think.
Oxfordshire and other councils must continue to reform the way they work to become more efficient, both in back-office functions and in front-line service delivery. Further savings do still need to be made, and with councils accounting for a quarter of all public spending they need to continue playing their part in tackling the deficit left by Labour.
The recent Spending Review included a package of measures to support local government, enabling them to streamline their asset base and invest in services.
We have made it possible for councils to sell property assets and use the capital to invest in transforming local services – and ensure further savings. We have introduced council tax flexibilities to help councils with the growing costs of adult social care. And by the end of this Parliament, councils will also keep 100% of local taxes including all £26 billion from business rates.
David Cameron discusses Britain's new runway with ITV Meridian political correspondent, Phil Hornby.Read the full story ›
A consultation has been launched today into plans to spend millions pounds tackling one of the region's worst traffic bottlenecks.
Rush hour congestion is a major problem on the A40 between Witney and Oxford - with thousands of vehicles using the single carriageway every morning during the week.
The options on offer include adding a new lane or creating tram or train links. Sam Holder reports.
Anti-fracking protesters have driven a tank to Prime Minister David Cameron's constituency home.
Fashion designer Vivienne Westwood was on board the tank to support the demonstration.
The protest outside Mr Cameron's Oxfordshire home is in opposition to the drilling for shale gas - a process known as fracking.
There are concerns that chemicals used during the drilling could harm the environment.
David Cameron made his comments about Operation Stack in London after the COBRA meeting.
David Cameron said he would be a proud to lead a majority Conservative government as he delivered his victory speech outside Number 10 this afternoon.
He said: "I truly believe we are on the brink of something very special in this country."
Earlier the Prime Minister arrived back at Downing Street with his wife Samantha after the meeting the Queen at Buckingham Palace.
Mr Cameron spent just over 20 minutes with the Queen after learning that the Tories had reached the 326 seats needed to command an absolute majority in the House of Commons.