Guidolin returns as Udinese coach
"A two-year contract has been agreed," an Udinese statement said.
Guidolin, who bossed Udinese in 1998-99, decided to quit Parma despite leading them to an impressive eighth place in their first season back in the top flight.
He joins an Udinese side which ended the season in 15th.
Coach Pasquale Marino had already announced that he was leaving Udinese and could now complete a swap move to Parma, although club officials have said no deal has been done.
Sampdoria have said they will announce their new manager this week after Luigi Del Neri quit the Champions League qualifiers for Juventus. Chievo boss Domenico di Carlo is seen as favourite in the media.