Despite the excellent nonlinear optical properties of BiB3O6 (BIBO) crystals, their wide application to nonlinear wavelength conversion has been limited because they are very susceptible to optical damage at moderate fundamental input power. Investigation of photo-induced damage to BIBO crystals showed that the optical damage was caused by photorefraction and could be repaired by annealing. BIBO crystals are more susceptible to optical damage in visible than in IR light. The present study suggests strongly that BIBO crystals can withstand much greater laser power at elevated temperatures without incurring any optical damage, which allows an increase in the nonlinear conversion efficiency and the maximum power of nonlinear waves. (C) 2008 Elsevier B.V. All rights reserved.