  We propose a new method for simulating QCD at finite density. The method is
based on a general factorization property of distribution functions of
observables, and it is therefore applicable to any system with a complex
action. The so-called overlap problem is completely eliminated by the use of
constrained simulations. We test this method in a Random Matrix Theory for
finite density QCD, where we are able to reproduce the exact results for the
quark number density.
