The effects of poly(L-lysine) as a biomolecular additive on the synthesis of LiNbO3 were investigated. PLL is a widely-studied biomolecule containing amino groups that can interact with solid inorganic clusters. The addition of PLL to a LiNbO3 precursor solution enhanced the aggregation of the produced LiNbO3 nanoparticles. This aggregation was induced by the electrical attraction of PLL with LiNbO3 nanoparticles, and was enhanced with increasing PLL molecular weight. Furthermore, the association of PLL with LiNbO3 nanoparticles was increased by the addition of methanol, which enhanced the miscibility of PLL with the precursor solution working as a co-solvent. The LiNbO3 nanoparticles generated with PLL exhibited piezoelectric properties without post-thermal treatment, suggesting that PLL contributes to the piezoelectricity. The results of this study are intriguing in terms of the potential for diverse engineering nanomaterials synthesis through a biomolecule that can also improve the physicochemical properties. (C) 2013 Elsevier B.V. All rights reserved.