The current oscillation was observed in modulation‐doped GaInAs/n‐GaAs strained‐layer superlattices when a high electric field was applied parallel to the layers. The critical voltage for the threshold of oscillation depended on the layer thickness. Observation of the propagation of a high‐electric‐field domain in the GaInAs layers shows that this phenomenon is the Gunn effect. Comparing with the high‐field effects in GaAs/n‐AlGaAs superlattices, we consider the role of the interface dislocations.