The Cu2ZnSiSe4 crystals were grown by chemical vapor transport using iodine as a transport agent. The temperature dependence of resistivity, ρ (T), was measured with the Van-der-Pauw method.figureFig. 1. Temperature dependence of the resistivity of Cu2ZnSiSe4. The shape of the temperature dependence of the resistivity (Fig. 1) exhibits two regions of different behavior. It can be demonstrated that in both regions conductivity is related to the hopping charge transfer. At high temperatures the nearest-neighbor hopping (NNH) conductivity is observed, whereas transition to the Mott variable-range hopping (VRH) conductivity takes place when T is decreased. Both types of the hopping conduction are analyzed by linearization of the temperature dependence of the resistivity and the local activation energy within different temperature ranges [1]. The results obtained with both methods agree well with each other. The NNH conductivity is observed unambiguously in samples SiSe1 and SiSe2 between T ~ 200 – 270 K, characterized by the activation energy E3 ≈ 61 and 82 meV, respectively. The Mott VRH conduction is observed in all investigated samples below T ~ 200 K and can be described by the characteristic temperature T04 = (2.6 – 5.1)×106 K, depending on sample. The bandwidth parameter, W0 ~ 190 − 240 meV, of the density of the localized states (DOS) is determined. The observed variation of T04 is attributable to proximity to the metal-insulator transition and/or variation of DOS at the Fermi level, whereas the large value of W0 indicates a high degree of disorder in the investigated material [1]. Financial supports from BMBF MDA11\002 projects are acknowledged. [1] B.I. Shklovskii, A.L. Efros. Electronic Properties of Doped Semiconductors. Springer, Berlin (1984).