[en] Changes in impurity state of In by gradual partial substitution of the matrix atoms have been studied in PbTe-based solid solutions (PbTe-SnTe, PbTe-PbSe and PbTe-PbSe-SnTe) containing up to 1% at. In. The Hall's coefficients, thermo-e.m.f. and electric conductivity of polycrystalline samples are measured. The results on trasfer effects in In-alloyed solid solutions may be treated in terms of the impurity state narrow band model, which is also applicable to the initial components (PbTe, PbSe and SnTe). The position of the impurity band essentially depends on composition of the solid solution. The rate of displacement of the impurity state energy is 0.25 eV for PbTe-PbSe and 0.4 eV for PbTe-SnTe. In a complex solid solution the displacement depends on joint effect of the components. Being only partially occupied, the In impurity band may efficiently compensate for the effect of other donors and acceptors. This permits to obtain samples with low concentration of carriers when the band is situated in the forbidden zone (Pbsub(1-x)Snsub(x)Te at 0.3 < or approximatelyx< or approximately0.4)