Hulkenberg begins his third season at his third different team, having raced for Williams in 2010 and Force India in 2012.
"The Sauber F1 Team made significant progress last year from 2011," he said.
"Now the team is ready to take the next step, and I want to play my part in making that happen. My personal aim is to put in a good, steady performance this season."
"We have had our eye on Nico for some time and have been impressed by his performances. He is very quick, but, most importantly, he’s also very efficient. He understands how to pick up as many points as possible from a particular race situation," she said.