A technically simple, one-step process for the preparation of hydrophobic cellulose-based fabrics via covalent surface modification is presented. A small aliphatic molecule was grafted onto the surface of various types of fabrics under mild processing conditions (room temperature, few seconds), leading to alteration of the surface properties. The modified fabrics displayed not only hydrophobic but also superoleophilic properties, meaning that these fabrics are ideal candidates for separation of oil-water mixtures. Separation efficiencies above 93% were achieved for the removal of common organic solvents and oils from aqueous solutions. In addition, separation efficiencies were unaffected by the exposure of the modified fabrics to elevated temperature and acidic conditions. Furthermore, all types of fabrics displayed high recyclability: oil-water separation efficiency did not deteriorate even after 30 separation cycles. The simplicity of the surface modification combined with the use of readily available and low-cost materials are promising characteristics for future practical applications.