  The equivalence between the Dirac method and Faddeev-Jackiw analysis for
gauge theories is proved. In particular we trace out, in a stage by stage
procedure, the standard classification of first and second class constraints of
Dirac's method in the F-J approach. We also find that the Darboux
transformation implied in the F-J reduction process can be viewed as a
canonical transformation in Dirac approach. Unlike Dirac's method the F-J
analysis is a classical reduction procedure, then the quantization can be
achieved only in the framework of reduce and then quantize approach with all
the know problems that this type of procedures presents. Finally we illustrate
the equivalence by means of a particular example.
