The complex admittance of ann‐type Hg1−xCdxTe/Photox SiO2interface withx=0.3 has been examined for frequencies ranging between 1 mHz and 4 MHz. The conductance method is used to decompose the total interface state density into three types of components: a valence‐band tail, a conduction‐band tail, and some well‐resolved discrete states. The fixed charge density is low and there is no statistical broadening. The surface valence‐ and conduction‐band edges are both found to be shifted upward in energy relative to their respective bulk values; moreover, the surface has converted toptype. The energy variation of the valence‐band tail states response times follows a pattern characteristic of Shockley–Read recombination centers with a constant capture cross section, but the behavior of the conduction‐band tail states is more complicated. Evidence is presented that the interface region has a higher Cd concentration than the bulk.