The aim of this work was the study of the surface modification of cotton fibers to confer hydro and oil repellency to the fabrics. A surface treatment not involving the bulk of the fibers was chosen, so fabrics can maintain comfort properties. Moreover the study focused on an economical and environmental friendly process, in order to obtain an effective treatment with good fastness to washing. A modified silica based film was applied on fibers surface by sol-gel, comparing laboratory grade reagents with a commercial product as precursors and optimizing process parameters. From obtained results sol-gel can be indicated as a promising process to confer an effective and durable finishing to cotton fibers with low add-ons. Long impregnation times can significantly improve the treatment fastness, while ironing the washed samples can restore, at least partially, hydro and oil repellency lost after the washing. Obtained results were supported by a deep surface characterization of untreated, treated and washed samples. The best results were obtained using the commercial product as the only precursor. This is interesting for an industrial application, due to the low cost of this product if compared with the laboratory grade reagents investigated. Some applications of finished textiles can be for household use, technical garments, umbrellas or outdoor textiles. (C) 2013 Elsevier B.V. All rights reserved.