The worms are for experiments that aim to help scientists understand why human muscles waste away in zero gravity. The species Caenorhabditis elegans, can sometimes be found in rubbish tips, where they feed on bacteria.
Atlantis launched at 1928 GMT (1428 EST) on Monday from the Kennedy Space Center near Cape Canaveral, Florida. This mission is dedicated to building up the store of replacement parts on the space station, which is nearing the completion of its construction phase.
A scarf belonging to American aviation pioneer Amelia Earhart has been brought along for the ride by mission specialist Randy Bresnik. Mr Bresnik's grandfather Albert was Earhart's only authorised photographer.
The six all-male crew of Atlantis will spend the US Thanksgiving holiday in orbit, as will the worms who are there for a study on muscle protein degradation.
