Lawrence Berkeley National Laboratory

We discuss dynamics of N=2 supersymmetric SU(n_c) gauge theories with n_f quark hypermultiplets. Upon N=1 perturbation of introducing a finite mass for the adjoint chiral multiplet, we show that the flavor U(n_f) symmetry is dynamically broken to U(r) times U(n_f-r), where r\leq [n_f/2] is an integer. This flavor symmetry breaking occurs due to the condensates of magnetic degrees of freedom which acquire flavor quantum numbers due to the quark zero modes. We briefly comment on the USp(2n_c) gauge theories. This talk is based on works with Giuseppe Carlino and Ken Konishi, hep-th/0001036 and hep-th/0005076.