The surface and surface layer of X-cut plates of congruent lithium niobate (produced by OAO Fomos Materials) have been investigated by structural and optical methods. It is shown that the plate surface is of high optical quality, comparable with that of foreign analogs. The existence of an oxygen-saturated (and, correspondingly, niobium-deficient) damaged surface layer with a depth of up to 20 μm is demonstrated. Ooptical waveguides have been designed based on the investigated crystal using the proton exchange method. The optical characteristics of these waveguides are comparable with those for Crystal Technology lithium niobate crystals; however, the proton exchange and annealing processes should be corrected. A comprehensive analysis of the Fomos Materials samples showed that they can be used to design integrated optical circuit elements for various instrumentation tasks.