Abstract: The present invention is directed to a liposomal delivery system comprising defined lipid components, including dimethyldioctadecylammonium and other lipid components and a stabilizing agent, which may be used in the delivery of bioactive agents to a subject in need thereof. The liposomal delivery system of the invention provide improvements in terms of delivery and stability. Ideally, the liposomal delivery system is used as a vaccine or drug/medicament delivery system although other bioactive agents may be delivered.