They are set to blast off into orbit in 2006 in a spacecraft which will spin around and create the gravity levels we would encounter on the red planet.
The idea is to see how the mice cope with the conditions. This will allow scientists to predict how a human would handle the Martian atmosphere.
The space mice - all females - will be exposed to Mars gravity for five weeks.
Each mouse will have its own living space, with toys to keep it amused.
'Alive and well'
The creatures' every move will be monitored by researchers.
After their five-week trip, scientists say the mice will return to Earth alive and well.