Lead indium niobate, Pb(In1/2Nb1/2)O3 or (PIN), is an interesting ferroelectric material, because it can be changed from a disordered state to ordered state by long-time thermal annealing. However, the temperature related to the maximum dielectric constant (Tmax) of PIN in relaxor phase is low (at 1 kHz, Tmax = 66 °C). In this study, to increasing Tmax of PIN, lead titanate, PbTiO3(PT) was thus added to PIN with compositions (1 - x)PIN-xPT (for x = 0.1-0.5). The influence of stress on the dielectric properties of (1 - x)PIN-xPT ceramics was then investigated. The dielectric properties were measured under various uniaxial compressive stress up to 400 MPa. The results showed that the superimposed compression load reduced the dielectric constant in 0.9PIN-0.1PT. For the other compositions, the dielectric constants first increased with the compressive stress, and then decreased when the stress was further increased up to 400 MPa. The dielectric loss tangent of all composition was found to decrease with increasing compressive stress. © 2008 Elsevier B.V. All rights reserved.