The effect of domain size on the dielectric and piezoelectric properties of [111]-oriented tetragonal Pb(In(1∕2)Nb(1∕2))O(3)-Pb(Mg(1∕3)Nb(2∕3))O(3)-PbTiO(3) crystals was investigated. The dielectric permittivity (ɛ(33 ) (T)∕ɛ(0)) and piezoelectric coefficient (d(33)) were found to be on the order of 13 800 and 1630 pC∕N, respectively, for samples with domain size of ∼500 nm, a 3-fold increase to crystals with domain size of ∼50 μm. Rayleigh analysis revealed that the extrinsic contribution to the piezoelectric response increased from ∼8% to 30% with decreasing domain size, due to the increased domain wall density and associated irreversible domain wall motion. The enhanced properties were thought to relate to the fine domain structures, however, showing a poor electric field and temperature stabilities with domain size of 500 nm. Of particular significance is that samples with domain size being on the order of 5 μm exhibit field and temperature stabilities, with yet high piezoelectric properties, make it potential for transducer applications.