The piezoelectric and mechanical properties of hot-pressed PZT-PYW were investigated. As the Pb(Y2/3W1/3)O-3 concentration increased, the piezoelectric constant(d(33)) also increased up to a concentration of 3 mol % PYW reaching a value of 485 x 10(-)12 CN-1, but beyond this concentration it continuously fell. A decrease in grain size with increasing Pb(Y2/3W1/3)O-3 content in the system changed the transgranular fracture mode to an intergranular fracture mode, resulting in an enhancement in K-1c from 0.83 MPam(1/2) at 1 mol % PYW to 1.1 MPam(1/2) at 3 mol% PYW. Consequently, the highest d(33) and K-1c values were obtained at the composition 0.97Pb(Zr0.52Ti0.48)O-3-0.03Pb(Y2/3W1/3)O-3.