Thin oxide coatings may be prepared from solutions of alkoxides by the sol-gel method. The procedure consists in the application of a thin liquid layer of solution to the substrate and in the subsequent gelation of this coating, which, upon drying and heating, transforms into a glass or a ceramic. The liquid film may be deposited by different techniques. Many different physical and chemical parameters may influence the thickness, structure and quality of coatings. Among these the chemical composition of the solutions, their reactivity, concentration, density, viscosity and surface tension, the temperature and humidity of the processing environment, the method of application of the coating to the substrate, must be taken into account. In this paper the sol-gel method for the deposition of thin coatings is described from the point of view of the influence of the most important process parameters on the quality and properties of products.