The pact will elevate US aid to Israel from $3.1bn a year currently to $3.8bn, officials say, but the Israelis had to make concessions to secure the money.
The agreement, to be signed on Wednesday, follows 10 months of talks.
It was approved despite frustration within the Obama administration at Israeli settlement building.
The agreement, which replaces a 10-year package set to expire in 2018, “constitutes the single largest pledge of bilateral military assistance in US history”, said the state department.
Israel will receive, among other things, $500m a year for missile defense programmes.
But the pact includes an undertaking that Israel will eventually spend all of the funds through the American defence industry, rather than its own military contractors.
Israel must also not seek additional funds from Congress beyond what will be guaranteed annually in the new package.
Mr Obama has sought to demonstrate his support for Israel’s security in order to undercut criticism that his administration has not been supportive of its Middle East ally.
Source : The BBC