The stability and size control of reverse vesicles have been investigated for a sucrose monoalkanoate/hexaethylene glycol hexadecyl ether/decane/water system, The stability is highly dependent on the surfactant mixing ratio, amount of added water, and vesicle size. The size distribution of reverse vesicles produced by simple mixing is very large, but larger vesicles can be removed by means of the extrusion method and reasonably homogeneously size-distributed reverse vesicles can be obtained. If a probe-type ultrasonicator is used, the reverse vesicles obtained are homogeneous and of very small size (50-70 nm in diameter) and they are considered to be of the unilamellar type.