A semi-empirical interatomic potential formalism, the second-nearest-neighbor modified embedded-atom method (2NN MEAM), has been applied to obtain interatomic potentials for Fe-Nb and Fe-Ti systems based on the previously developed potentials for pure Fe, Nb and Ti. The present potentials generally reproduce the fundamental physical properties of the Fe-Nb and Fe-Ti systems accurately. The potentials can be easily combined with already-developed MEAM potentials for binary carbide or nitride systems and can be used to describe Fe-(Ti,Nb)-(C,N) multicomponent systems.