A microscopic model of the drift mobility in Hg1−xCdxTe (x ≈ 0.2) is established on the basis of the Kohler variational method. The relevant scattering michanisms, degeneracy, Kane band structure, and structural point defects are included. The dependence of the electron mobility on the Fermi level position is investigated. The model is compared with experimental Hall data taking into account calculated Hall factors. The spatial variability of electron and heavy hole drift mobilities in a 1Dn+n− p‐junction diode is demonstrated. The mobility routine, which can easily be modified for other materials, will be applied in a 2D device simulation package.