Abstract. The physical properties (viscosity, density, electroresistivity and magnetic susceptibility) of pure tin, copper, silver, some binary (Sn -Ag, Sn -Cu, Sn -Bi, Sn -Zn) and ternary (Sn-Ag-Cu, Sn-BiAg, Sn-Bi-Zn) alloys with near eutectic compositions are investigated in wide temperature ranges. The irreversible decrease of viscosity in pure tin melt is discovered at 820 0 С during heating. The similar anomaly with the following hysteresis of dynamic viscosity was fixed for binary and ternary alloys but at higher temperatures -900 0 С and 950 0 С respectively. For all the systems it was shown that the alloys with eutectic compositions differ significantly in their electric and magnetic properties from hypo-and hypereutectic ones. Qualitative and quantitative metallographic analysis for Sn-3.8wt.%Ag-0.7wt.%Cu samples, heated low and above characteristic temperatures, showed the influence of melt overheating on crystallization kinetics. . Introduction.Because of the toxicity of lead, traditional Sn-Pb solders are now being replaced with Sn-base soldering alloys containing additions of other metals (Ag, Bi, Zn etc.), see, for example, [1][2][3][4][5]. In Europe the extensive search for new lead-free soldering materials is now coordinated by COST Action MP0602 till 2011. However, physical properties of these new solders at high temperatures, especially in liquid state, are practically unknown. In this paper we present experimental results on density (obtained by gamma-penetration method), viscosity (by torsion oscillation method), electroresistivity (by contactless method in rotating magnetic field) and magnetic susceptibility (by Faraday's method) for pure liquid tin, copper and silver, some binary (Sn-Ag, Sn-Cu, Sn-Bi, Sn-Zn) and ternary (Sn-Ag-Cu, Sn-Bi-Ag, Sn-Bi-Zn) alloys with near eutectic compositions in wide temperature ranges.