Cellulose fabric is rapidly made water-repellent by direct acylation with isopropenyl stearate, which is representative of isopropenyl esters of long-chain fatty acids. The esterification produced a material with minor change in tensile strength. Acylation by isopropenyl stearate (IPS) was accomplished by transfer of reagent to cloth followed by heat- curing in an acid-catalyzed reaction. The low levels of catalyst (0.05% by weight of IPS), short curing periods (7-60 s), and low heating temperatures (~180°C) provided conditions for chemical incorporation of a fatty acid at low levels of substitution (DS < 0.001).