By DTA, X-ray diffraction, EMF methods and microhardness measurements, the phase equilibria on the concentration sections Tl 5 Te 3 -Tl 4 PbTe 3 -Tl 9 BiTe 6 (I), Tl 2 Te-Tl 4 PbTe 3 -Tl 9 BiTe 6 (II), Tl 5 Te 3 -Tl 9 NdTe 6 -Tl 9 BiTe 6 (III) and Tl 2 Te-Tl 9 NdTe 6 -Tl 9 BiTe 6 (IV) of the multinary systems Tl-Pb(Nd)-Bi-Te were investigated. A number of isopleth sections, projections of liquidus and solidus surfaces of the systems (I)–(IV) were constructed. The concentration dependences of crystal lattice parameters, microhardness and of partial thermodynamic functions of thallium ( Δ G ¯ , Δ H ¯ , Δ S ¯ ) in alloys were determined. The investigated systems are characterized by formation of continuous (I, III) or wide (II, IV) areas of solid solutions based on Tl 5 Te 3 compound.