AlN/GaAs heterointerfaces formed by LCVD were investigated by the correlation DLTS technique. Three methods were used to distinguish between the signals from bulk traps and from interface traps, including comparison of the signals from Schottky and MIS diodes, variation of pulse height and different GaAs surface treatments. The surface potentials determined by Arrhenius plots agree well with those determined by the conventional high frequency method. Interface traps measurable by the correlation DLTS method lie in the energy range Ec - 0.69 to 0.6 eV with densities of 3 × 1012 and 2 × 1013 eV-1 cm-2 at the respective extremities. Capture cross-sections are determined to be about 10-13 cm2 by the small pulse ERDLTS method, while time constants exponentially decrease from midgap reaching 2.1 μs at Ec - 0.6 eV.