John Collins, 74, Terry Perkins, 67, Brian Reader, 76, and Daniel Jones, 58, pleaded guilty at Woolwich Crown Court.
Items believed to be worth more than Â£10m were taken in the raid at Hatton Garden Safe Deposit Company in London's jewellery quarter.
More than 70 safety deposit boxes were ransacked.
Perkins, of Heene Road, Enfield, Collins, of Bletsoe Walk, Islington, Jones, of Park Avenue, Enfield and Reader, of Dartford Road, Dartford, were arrested in May.
They pleaded guilty to conspiracy to burgle, namely to enter Hatton Garden Safe Deposit in London with intent to steal, between 1 January and 7 April.
The four men also faced a charge of conspiracy to convert or transfer criminal property, but the prosecution said they would not pursue the charge in light of the men's guilty pleas in relation to the conspiracy to burgle charge.
Earlier this month a law firm confirmed the Hatton Garden Safe Deposit had gone into liquidation as the company was insolvent and "owes money to companies and people".
The men will be sentenced at a date to be confirmed.
After the burglary, the Met Police launched an investigation into why after police were made aware an intruder alarm had gone off at the scene of the raid it was decided the alarm did not require a response.
The force apologised for not following procedures and said it would investigate why the call was given a grade that meant no police response was deemed necessary.
Five other men still face trial accused of conspiring to commit the burglary, a charge they deny.
Hugh Doyle, 48, of Riverside Gardens, Enfield, north London; William Lincoln, 60, of Winkley Street, Bethnal Green, east London; and John Harbinson, 42, of Beresford Gardens, Benfleet, Essex, all also deny the laundering offence and are due to stand trial in November.
Paul Reader, 50, of Dartford Road, Dartford, and Carl Wood, 58, of Elderbeck Close, Cheshunt, Hertfordshire, are yet to enter pleas.
Perkins' daughters also appeared in court, along with their husbands, accused of conspiracy to convert or transfer criminal property between 1 January and 19 May.
Brenn Walters, also known as Ben Perkins, 43, and Laura Perkins, 40, both of Manor Court, Enfield, north London, and Terri Robinson, 35, and Steven Robinson, 46, both of Sterling Road, Enfield, were charged in connection with the raid last month.
Four men have admitted conspiracy to burgle in connection with the Hatton Garden safety deposit box raid over the Easter weekend.