A photochemical reaction, which generates surfactant molecules which then spontaneously assemble into vesicles, is described. Upon irradiation of a dispersion of the photocleavable water-insoluble precursor didecyl-2-methoxy-5-nitrophenyl phosphate, the phosphate-phenolate bond was selectively hydrolyzed and didecyl phosphate was released in the medium. Light microscopy was used to assess the presence of vesicles, which were generally in the range of 1-10 mu m This light-induced formation of vesicles is of general interest in the field of liposomes technology and may be seen as an additional contribution to the prebiotic chemistry of compartimented bilayer formation.