  We propose a number of new Seiberg dualities of N=1 quiver gauge theories.
The new Seiberg dualities originate in new S-dualities of N=2 superconformal
field theories recently proposed by Gaiotto. N=2 S-dual theories deformed by
suitable mass terms flow to our N=1 Seiberg dual theories. We show that the
number of exactly marginal operators is universal for these Seiberg dual
theories and the 't Hooft anomaly matching holds for these theories. These
provide strong evidence for the new Seiberg dualities. Furthermore, we study in
detail the Klebanov-Witten type theory and its dual as a concrete example. We
show that chiral operators and their non-linear relations match between these
theories. These arguments also give non-trivial consistency checks for our
proposal.
