Certain phosphate bipolar amphiphiles, both monomeric (I and II) and polymeric or rather oligomeric (poly-I and poly-II), were used as basic materials for the preparation of simple and mixed vesicles. Specifically, it was found that oligomeric phosphate bipolar amphiphiles form stable vesicles in aqueous media. The same oligomeric bolaamphiphiles in mixture with their monomeric counterparts also form stable mixed vesicles with sonication; they are relatively less stable with the "thin film method." Furthermore, it was shown that the method of spanning the membrane of didodecylphosphate vesicles with the dipolar amphiphile II is not effective for enhancing stability.