Lithium niobate exhibits low reactivity with most chemical etchants. Consequently, etching a LiNbO3 surface to produce optical structures such as ridge waveguides or grooves for fiber coupling normally requires relatively slow processes such as ion milling. We have developed a laser-driven chemical etching process for etching highly unreactive ionic solids based on the fusion of salts In the molten phase and show that the etch rate can be more than 100 times faster than ion milling rates. This process involves spatially localized melting of LiNbO3 by high-power density laser pulses with photon energies in excess of the band gap of LiNbO3. While molten, LiNbO3 undergoes reaction with a surface coating of KF to form niobium oxyfluoride anions by fusion of the salts. The resulting solid is highly water soluble. The insolubility of LiNbO3 permits subsequent removal of only the irradiated area by rinsing in water. Surface morphology is determined by laser power density. The process exhibits a wavelength dependence.