The company indicated Airbus' production delays as the reason for the decision, and said in a statement on Tuesday that its FedEx Express unit has ordered 15 Boeing 777 freighters and taken options on an additional 15.
"The availability and delivery timing of this aircraft, coupled with its attractive payload range and economics, make this choice the best decision for FedEx," said Frederick Smith, FedEx chief executive.
Barbara Kracht, Airbus company spokesperson said: "Airbus regrets the decision by FedEx, but we understand their need to urgently address their capacity growth."
The European plane maker, which is owned by European Aeronautic Defense & Space Company, recently announced that production for the A380 jet will be delayed by two years.
To streamline production, Airbus announced on Monday that it will slash the number of suppliers it uses from 3,000 to 500.
Boeing said delivery of its aircraft to FedEx Express will begin in 2009.
"We're looking forward to working with FedEx on this new chapter in our relationship," said Ray Conner, vice president of sales for the Americas for Boeing Commercial Airplanes.
Emirates, which has ordered 45 of the A380s and is the programme's largest customer, said last month it would send a team of technicians to France to assess the accuracy of promised delivery dates for the A380 superjumbo.
Virgin Atlantic Airways also said last month it would defer the delivery of the first of its six Airbus A380 superjumbo jets until 2013.
Airbus had previously taken a total of 167 firm orders for the A380, including an eight-plane order from Qantas Airways announced last month.