  The Time of Flight (TOF) system of the AMS experiment provides the fast
trigger to the detector and measures the crossing particle direction, velocity
and charge. AMS was operated aboard of the shuttle Discovery on June 1998 (NASA
STS-91 mission) and will be upgraded and installed on the International Space
Station at the end of 2003, for 3 years of data taking. The performances of the
TOF during the precursor flight and modifications needed in the final version
of the detector are presented.
