The new proposed experiment CLEO-c in the Wilson Laboratory at Cornell University will explore the physics potential of the CLEO detector and the CESR storage ring operation in the center-of-mass energy range 3 - 5 GeV. Data taking could start as early as 2003. Estimates of the luminosity that a suitably modified CESR can deliver in this energy range imply data samples of 1 - 4 fb^-1 /year. The physics program of CLEO-c can be divided in two parts: weak interaction physics and QCD physics. Both programs will be presented and discussed.