Various PZT/epoxy 1-3 composites were investigated for high power applications. "Hard" lead zirconate titanates (PZT4 and PZT8) were chosen for active piezoelectrics owing to their high mechanical quality factors, Qms, while the passive polymers were selected based on the desired properties for high power composites - low elastic loss, low elastic modulus and high thermal conductivity. The results demonstrated that the composites with high thermal conductivity polymers generally have degraded electromechanical properties with significantly decreased mechanical quality factors, whereas the composites filled with low loss and low moduli polymers were found to have higher Qms with higher electromechanical coupling factors kt: Q m ∼ 200 and kt ∼ 0.68 for PZT4 composites; Q m ∼ 400 and kt ∼ 0.6 for PZT8 composites. The effects of high drive field on the behavior of 1-3 composites were further investigated by varying active and passive components. Improved high power characteristics of 1-3 piezoelectric composites were achieved by selection of optimized composite components, with enhanced electromechanical efficiency and thermal stability under high drive conditions.