Tunneling transport assisted by the Coulomb interaction of Wannier–Mott exciton is investigated within the framework of the sequential tunneling formalism. The exciton-assisted tunneling (EAT) probability is derived from Bardeen’s transfer Hamiltonian. The EAT-induced current-voltage(I-V)characteristics are evaluated using a set of three-particle rate equations for double-barrier and triple-barrier tunneling structures. We found that the EAT results in additional current at low bias voltages with respect to the resonant tunneling (RT) current. Their offset in theI-Vspectra is associated to the exciton binding energy. The current intensity of the electron EAT is dependent on the quantum-well hole density as well as the exciton Bohr radius. CalculatedI-Vcharacteristics of electron tunneling via the heavy-hole excitonic states are presented and discussed for typical AlxGa1−xAs/GaAs nanostructures. In particular, the line shape of the EATI-Vspectra is shown to have a fingerprint distinguishable from that of the RT at low temperature. ©1997 American Institute of Physics.