The 787 Dreamliner was grounded after two incidents in January in which batteries caught fire or emitted smoke.
The Federal Aviation Administration said in a news release it will issue instructions next week to operators "for making changes to the aircraft and will publish in the Federal Register the final directive that will allow the 787 to return to service with the battery system modifications. The directive will take effect upon publication."
The announcement said the FAA will require airlines operating the 787 to "install containment and venting systems for the main and auxiliary system batteries, and to replace the batteries and their chargers with modified components."
FAA Administrator Michael Huerta said the decision to approve the design modification came after FAA certification specialists "observed rigorous tests we required Boeing to perform and devoted weeks to reviewing detailed analysis of the design changes."
Citing people briefed on the matter, The New York Times said Friday Huerta and Transportation Secretary Ray LaHood were satisfied the changes Boeing proposed would virtually eliminate concerns the lithium-ion batteries could burst into smoke or fire.
The FAA said Friday it will monitor modifications on the aircraft in the U.S. fleet, sending inspectors to locations where modifications are being made.
"Any return to service of the modified 787 will only take place after the FAA accepts the work," the statement said.
As the certifying authority, the FAA will continue to support other authorities around the world as they finalize their own acceptance procedures.