The Italian has left the Stadium of Light after just six months, with the Black Cats currently 19th in the Premier League table after a poor first half of the season
A statement on the club's website read: "Sunderland AFC has announced that the club has parted company with Director of Football Roberto De Fanti.
"The club would like to place on record its thanks to Roberto and wishes him well for the future."
The Italian joined the Black Cats in June of last year, in a newly created director of football role, arriving at the same time as chief scout Valentino Angeloni, the pair having worked together previously at Udinese and Inter.
De Fanti oversaw a busy summer of transfer activity in the summer with Sunderland, bringing in 14 new players including the likes of Fabio Borini, Vito Mannone and Ki Sung-Yueng.
However, despite the influx of players, the club are currently struggling in the Premier League table, joint-bottom with Crystal Palace on 17 points after 21 games.