A novel anodic sulfidization process for forming native sulfide films on Hg1−xCdxTe is described. In the new process native sulfide films rather than native oxides terminate the lattice and passivate the surface. The results of Auger electron spectroscopy analysis indicate that native homogeneous CdS films are formed with an abrupt interfacial transition. The measured capacitance‐voltage characteristics of metal‐insulator‐semiconductor devices indicate that the films have a low negative fixed surface charge density of the order of –1×1011e cm−2and a relatively low concentration of fast surface charge density. The native sulfide films leave the surface ofp‐type Hg1−xCdxTe practically at flat band and in this respect are superior to native oxide films which invert the surface ofp‐type material. The new surface passivation is in particular suitable for photovoltaic diodes implemented onp‐type Hg1−xCdxTe.