Former Italy forward Quagliarella, who is the top Serie A scorer still playing, joined the Genoa-based outfit in 2016 from Torino.
“To the satisfaction of all, the striker with 233 appearances and 99 goals in our jersey has committed to Sampdoria until June 30, 2022,” the club said.
Quagliarella, who turns 39 in January, has spent his entire career in Italy with clubs including Juventus, Udinese, and Napoli.
He won three Serie A titles with Juve between 2010 and 2014, before moving to city rivals Torino, and back to Sampdoria in 2016, where he had a brief spell earlier in his career.
Last season Quagliarella netted 13 goals to bring his tally to 177 in 500 Serie A matches. He leads Lazio’s Ciro Immobile (155) and AC Milan’s Zlatan Ibrahimovic (147) in the Italian top-flight’s all-time list of active scorers.
Currently 14th overall among the all-time scorers in the competition, he needs 12 more goals to join the top 10.
He was Serie A’s top scorer in the 2018-19 season with 26 goals.