The sequential tunneling of electrons through Schottky diodes with GaAs/AlGaAs multiple quantum wells (MQWs) is reported. Two series of tunneling structures were observed in low-temperature current-voltage (I-V) characteristics in 200-Å-period MQWs. The oscillations in the conductance (G) were found to be persistent from 5 K up to 200 K. S-shape features in the current-voltage characteristics similar to those observed from double-barrier resonant tunneling structures were observed at low temperature in the MQW structures. The electron tunneling process through the MQW structures is discussed in terms of the creation and propagation of high-field domains as a function of the applied bias.