PbZrO3 and mixed PbZr1-x Sn (x) O-3 single crystals were grown by means of high temperature solution growth technique. A spontaneous crystallization was carried out in a Pt crucible, with PbO as a solvent. Electrical as well as thermal and dielectric properties were investigated in terms of Sn concentration. The measurements have been made in the large temperature range between 120 K and 800 K. The temperature dependences of c (p) for investigated crystals can be approximated by the Einstein function and at high temperatures (cubic phase) c (p) reaches the classical Dulong-Petit limit value similar to 125 J/mol K. From electrical measurements the ac and dc conductivity and the activation energies have been calculated and attributed to different types of electrical conductivity.