In this work, we report on the fabrication and characterization of surface microstructures in lithium niobate thin films and single crystal by using KrF excimer laser ablation technique at 248 nm with 6 ns pulse width. Ablation is carried out through a mask projection set-up. Various experimental conditions are used in order to evaluate the potential of laser direct writing for photonic waveguides fabrication in lithium niobate. The surface morphology of the processed structures was studied by optical and atomic force microscopy. Laser processing mechanism is investigated by using micro-Raman spectroscopy. (c) 2007 Elsevier B.V. All rights reserved.