Single crystal growth of LiB3O5 (LBO) by top-seeded solution growth technique has been investigated using a boron oxide-rich solution. The X-ray diffraction measurements and differential thermal analysis performed on different samples have revealed the strong dependence of crystal quality on phase purity of the starting charge used for growth and the thermal treatment of the solution. In the case of LiB3O5 charge synthesized by the solid-state sintering method, Li2B4O7 and Li2B8O13 impurity phases are found to be present in significant amount. The results show that the presence of Li2B4O7 in the solution promotes the growth of polycrystalline LBO by providing uncontrolled sites for crystallization. (C) 2004 Elsevier B.V. All rights reserved.