The Sauber C23 was a Formula One racing car designed by Sauber for the 2004 Formula One season. The C23 was driven by Giancarlo Fisichella, who left his previous team Jordan to join Sauber. Felipe Massa, who was a regular driver for Sauber in 2002, returned to Sauber after spending a year as a test driver for Ferrari. Neel Jani was the team's test driver.