He lost it on a flight from Philadelphia to Texas.
But Hansen still has more than a Speedo to show for his Olympic triumph in Beijing.
He's gotten his medal back thanks to an honest fellow passenger.
A young woman found the medal on a Southwest Airlines flight and contacted police, who put her in touch with the University of Texas athletic department.
Hansen met the student, got his medal back and gave her a reward.
The student says she'll donate the money to charity.
Hansen won his medal as part of the 400-meter medley relay, the race that gave Michael Phelps his record eighth gold.