The Argentina international will continue his career at last year's Ligue 2 champions, who have been in the market for a goalkeeper, as Sampdoria have confirmed his departure
The ambitious Ligue 1 side were keen to add a new goalkeeper to their squad before the closure of the summer transfer window and had previously been linked with Barcelona's Victor Valdes.
They turned their attention to Romero after Valdes opted to stay at Barca for one additional season and have now completed the signing of the Argentina international.
"Sampdoria can communicate that Monaco have acquired the sporting rights of Sergio Romero on a temporary basis with an option to buy," a statement on the official Sampdoria website reads.
The 26-year-old started his professional career at Racing Club, but made the move to Europe in 2007 when he joined AZ.
He won one Eredivisie title with the Alkmaar side before joining Sampdoria in the summer of 2011.