The interactions between thin Ge overlayers and both cleaved and ion‐sputtered Hg1−xCdxTe surfaces have been examined using synchrotron radiation. Ge forms an unreactive layer on cleaved substrates ofx=0.21 andx=0.28 with only a small loss of Hg (∼20%) from the interface. In contrast, deposition of Ge onto sputtered substrates results in approximately two (x=0.21 material) or three (x=0.28 material) times the Hg loss relative to the clean surface. The difference in behavior of the sputtered and cleaved material is due to sputter‐induced defects at the surface. The increased loss of Hg from the sputteredx=0.28 material is a result of a greater number of these defects caused by the weaker Hg–Te bonding and the corresponding increase in the preferential sputtering of Hg from the surface. No difference was observed between sputteredp‐type andn‐type material. These results are a consequence of GeTe and HgTe having very similar heats of formation; as such, deposition of Ge provides an indication of the reactivity of (HgCd)Te surfaces.