We have used the DLTS capacitance spectroscopy technique to search for interface states associated with an LPE GaAs/Al0.22Ga0.78As heterojunction. The results can be interpreted in terms of well‐known deep bulk states shifting abruptly at the interface with no observable interface states. The limiting values are <5×108and <4×109cm−2interface states (deeper than 0.1 eV) in the upper and lower half of the gap, respectively.