The Scudetto holders, who paid a €1.5 million fee for the temporary addition, have the option to sign the Argentine from Udinese at the end of 2014-15
The 23-year-old underwent a medical with the Scudetto holders earlier this week and the confirmation was merely a formality for the Argentine, who has impressed in Serie A since joining Udinese three years ago from River Plate.
Massimiliano Allegri's men could extend his year-long stay in Turin by an additional five seasons should they want to but it will set them back at least another €14m, with the possibility that he will cost €17m overall by 2020.
"Juventus can today announce that Roberto Maximiliano Pereyra has completed a move to the club after terms were agreed with Udinese on a one-season loan deal for a fee of €1.5 million," the club confirmed on Friday.
"The agreement includes the option for Juventus to make the deal permanent at the end of the 2014/15 campaign for a price of €14m, to be paid over the course of three years.
"This fee could be increased by €1.5m should Pereyra achieve certain predefined sporting targets by 30 June 2020."
Pererya is the latest high profile player to be brought on board since Antonio Conte's resignation last week, following in the footsteps of veteran left-back Patrice Evra from Manchester United and young striker Alvaro Morata from Real Madrid.
The uncapped Argentine will be hoping to help the Bianconeri secure a fourth straight Scudetto in 2014-15, albeit with a different coach from the previous three following Allegri's arrival in place of the departed Conte.