Sauber have retained current drivers Marcus Ericsson and Felipe Nasr for the 2016 season.
The duo arrived this term and have already amassed more points than Esteban Gutierrez and Adrian Sutil managed throughout the whole of last year.
Ericsson, who was signed from the now-defunct Caterham outfit, revealed his delight at signing a new contract with the Hinwil team.
"I'm very happy that the Sauber F1 Team has put its trust in my potential for another year," he told Sauber's official website. "Up to now I have some good memories of my first year with the long-standing Swiss team.
"I had a great start from the very beginning, and it is worth mentioning my first points in Formula One that I scored right away during the season opener.
"I am getting to know everyone within the team more and more, and feel I am being appreciated as a valuable driver. I feel honoured to be part of the Sauber Motorsport family, and I will continue to do my very best to succeed."
Meanwhile, Nasr is hoping to build on his solid maiden campaign to date by increasing his performance levels further in the second half of the season.
"It is great to be driving another season for the Sauber F1 Team," the Brazilian said. "The extension to the contract with the Sauber F1 team is an important step in my career.
"During the first half of the season, in what is my rookie year, I was able to gain a lot of experience from a driving perspective as well as on the personal side.
"Now I am looking forward to the second half of the season. My objective is to support the team as best I can, and also with regard to the development of the new car."
Sauber are currently ranked seventh in the team standings for 2015.
