The synthesis of 1,3-diundecanoyloxyacetone (1) and 1-undecanoyloxy-3-hydroxyacetone (2) is reported. The properties of 1, spread as a pure monomolecular film and in mixed films with stearic acid, were determined and evaluated. Compound 2 did not form films. The compounds were designed to exert, potentially, long-lasting insect-repellent activity subsequent to anchoring to the skin.