Models describing the point defects in rare-earth metal Ln (Sm, Gd, La, Pr) doped lead telluride crystals have been developed. The parameters of the charge disproportionation of the additives and their impact on the conductivity type in р-PbTe:Ln crystals were determined. Based on the proposed crystal-quasi-chemical formulae, the dependencies of the concentration of point defects and free carriers and the Hall concentration of current carriers on the doping agent content were calculated. Lead telluride / Rare-earth metals / Point defects / Crystal-quasi-chemical formulae