Viviano moves to Sampdoria after an unsuccessful stint with Palermo, the majority of which he spent out on loan.
The 28-year-old made 20 appearances for Palermo after joining the Sicilian club in January 2012, but was loaned out for the following two seasons to Fiorentina and Arsenal respectively.
However, his loan spell at Arsenal last season ended with him never playing a game for the Premier League outfit, and he will now attempt to turn his career around at the Stadio Luigi Ferraris.
A statement on Sampdoria's official website read: "On the day of the 68th birthday of Sampdoria, president Massimo Ferrero gifts [coach] Sinisa Mihajlovic and all the Blucerchiati fans official confirmation of the signing of Emiliano Viviano.
"The goalkeeper, who arrives from Palermo and has chosen the number two shirt, will be presented to the media tomorrow [Wednesday]."
Sampdoria begin their Serie A campaign at Palermo on Sunday August 31.
