According to the US Defence Security Cooperation Agency, the Government of Saudi Arabia is asking for technical services to "recertify the functional shelf life of up to 300 Patriot guidance enhanced missiles and associated equipment".
The estimated cost is $130m, the Agency said, adding that the proposed sale was still to receive approval from the US Congress.
"The proposed recertification program will allow the Royal Saudi Air Defence Forces to extend the shelf life of the PAC-2 missiles in its inventory for an additional 12 years," it said in a statement.
The Agency said the principal contractor would be Raytheon Corporation, based in Massachusetts.
Earlier this week, Saudi Arabia said it was interested in ordering $300m worth of military equipment spare parts from the United States.
The Agency said the Government of Saudi Arabia has requested a possible sale of spare parts in support of M1A2 Abrams tanks, M2 Bradley fighting vehicles, high mobility multipurpose wheeled vehicles, equipment, support vehicles and other related logistics support.