Relaxor based Pb (In0.5Nb0.5) O3 -Pb (Mg1/3 Nb2/3) O3 - PbTiO3 ternary single crystals (PIN-PMN-PT) were reported to have broader temperature usage range (TR-T) and comparable piezoelectric properties to Pb (Mg 1/3Nb2/3) O3 - PbTiO3 (PMNT) crystals. In this work, the orientation dependent dielectric, piezoelectric and electromechanical properties for PIN-PMN-PT crystals were investigated along ��� 001 ��� and ��� 110 ��� directions. The electromechanical couplings k33 and k32 for ��� 110 ��� poled crystals were found to be 0.91 and 0.91, respectively, with piezoelectric coefficients d33 and d32 on the order of 925 and -1420 pC/N. Of particular significance was the mechanical quality factor Q33 for ��� 110 ��� oriented crystals, which was found to be 500, much higher than the Q values of ��� 001 ��� oriented relaxor-PT crystals (Q���70-200). The temperature dependence of the piezoelectric properties exhibited good temperature stability up to their ferroelectric phase transition TR-T ���125 ��C, indicating ��� 001 ��� and ��� 110 ��� oriented PIN-PMN-PT are promising materials for transducer applications, with the latter for high power resonant devices where low loss (high Q) was required. �� 2009 American Institute of Physics.