  We explore the dynamics of three-dimensional Chern-Simons gauge theories with
N=2 supersymmetry and matter in the fundamental and adjoint representations of
the gauge group. Realizing the gauge theories of interest in a setup of
threebranes and fivebranes in type IIB string theory we argue for a Seiberg
duality that relates Chern-Simons theories with non-trivial superpotentials.
