The influence of SrO-WO3 additive on the piezoelectric properties and electric conductivity of lead zirconate-titanate (PZT) near the morphotropic phase boundary was investigated. Starting from the composition 0.995 Pb(Zr0.525Ti0.475)O-3 + 0.015 SrO + 0.005 WO3 (corresponding to 0.5 mol% of Sr3WO6) the fraction of WO3 was increased until Sr:W = 1:1. These samples were compared to a set of samples of PZT with WO3 addition but without SrO. Sr3WO6 has pseudocubic K2NaAlF6 structure with part of the strontium being octahedrally coordinated. In a solid solution with PZT this opens the possibility of realizing Sr on a B-site adjacent to a B-site occupied by W. Piezoelectric properties were measured on sintered disc samples under high field conditions. Impedance spectroscopy was used to investigate the conductivity and dielectric properties of the ceramics at various temperatures. The combined addition of SrO and WO3 increases the piezoelectric strain compared to samples of PZT with WO3 addition only. The results in polarization and conductivity indicate that the donor effect of WO3 is counteracted by the addition of SrO.