British auction house Bonhams is selling the napkin in an online auction from March 18-27 on behalf of Horacio Gaggioli, an agent from Messi's home country of Argentina who was part of the deal.
The starting price is STG300,000 pounds ($A582,000).
The napkin, bearing the date December 14, 2000, bears the signatures of Gaggioli, another agent, Josep Maria Minguella and Barcelona's then-sporting director, Carles Rexach, who met at a tennis club in Barcelona.
It outlines an agreement in principle to sign Messi and was intended to reassure his father, Jorge Messi, the deal would go through. A more formal and detailed contract with the club followed soon after.
"This is one of the most thrilling items I have ever handled. Yes, it's a paper napkin, but it's the famous napkin that was at the inception of Lionel Messi's career," Ian Ehling, the head of fine books and manuscripts at Bonhams New York, said in a statement.
"It changed the life of Messi, the future of FC Barcelona, and was instrumental in giving some of the most glorious moments of football to billions of fans around the globe."
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