The couple was appointed to the role in early 2008 on a three year contract and the stars have since been credited with bringing the talents of director Steven Soderbergh and actor Phillip Seymour Hoffman to the theatre group, as well as winning the patronage of Italian fashion designer Giorgio Armani.
Praising the pair's efforts, Sydney Theatre Company boss Ian Darling says, "In their first two years they've transformed the company and the way many people feel about it.
"I'm pleased they will stay to build on what they have already achieved in terms of quality and diversity of productions, artform development and education."
And Blanchett and Upton are delighted to continue their work with the theatre.
In a statement, the stars say, "It is a really great privilege to lead Sydney Theatre Company. We hope more and more people, especially those in Sydney, will find their way to the company and join us on this incredible ride."