  Motivated by the duality conjecture of Dijkgraaf and Vafa between
supersymmetric gauge theories and matrix models, we derive the effective
superpotential of N=1 supersymmetric gauge theory with gauge group SO(N_c) and
arbitrary tree level polynomial superpotential of one chiral superfield in the
adjoint representation and N_f fundamental matter multiplets. For a special
point in the classical vacuum where the gauge group is unbroken, we show that
the effective superpotential matches with that obtained from the geometric
engineering approach.
