Abstract: Microemulsions, similar in chemical composition to the lipid portion of low density lipoprotein (LDL), but not containing the protein portion, can be used as vehicles for the delivery of chemotherapeutic or diagnostic agents to neoplastic cells, while avoiding normal cells. When these artificial microemulsion particles are injected in the bloodstream or incubated with plasma, they incorporate plasma apolipoproteins on to their surface. The microemulsions can then be incorporated into cells via receptors for LOL and deliver molecules which are incorporated in the core or at the surface of the microemulsion.