We calculate the one-loop effective potential for a matter scalar field in the N=2 supersymmetric Maxwell-Chern-Simons model. It is found that the degeneracy of the classical potential is not lifted by radiative corrections. We show that reduction to the effective potential for the Chern-Simons theory as a limit from the Maxwell-Chern-Simons theory gives rise at one loop to an expression that differs from the result obtained solely within Chern-Simons theory.