Veteran defender Naldo has agreed a new deal with Schalke to take him through to 2020.
The 36-year-old joined from Wolfsburg in 2016 and has established himself as a fans' favourite at the Veltins-Arena.
"I am overjoyed at extending my time here at Schalke," he said.
"It is an enormous club with unbelievable, loyal fans who are always behind us."
Coach Domenico Tedesco added: "It is great news for all Schalke fans. Naldo is an outstanding person both on and off the pitch. He is a unifying figure in the squad."
Naldo helped Schalke to finish second in the Bundesliga last season, but their start to the 2018-19 campaign has been less impressive.
The 1-0 win over Mainz at the end of last month broke a five-game losing streak in the league, though they followed that up with another victory at Fortuna Dusseldorf before the international break.
Tedesco's side host Werder Bremen on Saturday.
