"Our aim can only be to fight for the championship," the German told reporters in a conference.
Mercedes, who have taken over champions Brawn GP, has signed Nico Rosberg as their second driver, after world champion Jenson Button left the British-base team for Mclaren.
Schumacher had planned a comeback with Ferrari earlier this year but soon changed his decision due to the neck injury he sustained in a motorcycle accident.
Former champions Damon Hill, Schumacher's major rival in the 90s, and Nigel Mansell have both said that age wouldn't play a factor
"It wouldn't surprise me if Michael challenged for another world championship," Britain's 1992 champion Mansell, who won his title aged 39 and competed in Formula One until the age of 41, said.
The sport's oldest champion remains the late Argentine Juan Manuel Fangio, who took his fifth title at the age of 46. The oldest driver to win a grand prix is Italian Luigi Fagioli in 1951 at the age of 53.
