A novel asymmetric Gemini surfactant, comprising two nonidentical hydrocarbon chain lengths and two different hydrophilic groups, abbreviated as C13COONa-O-C8BSO3Na, has been synthesized. The unique aggregation behavior was investigated by transmission electron microscopy in aqueous solution. Spontaneous vesicle formation (approximately 100-300 nm) was observed. The reversible morphological change of vesicle aggregation took place by varying the solution pH. These results indicated the potential application of the present amphiphile, which may be used as a model for cell membranes and drug delivery systems.