The anti-fungal agent amphotericin B (AmB) can be administered to patients in aqueous solution complexed with cholesteryl sulfate (CS), and this formulation helps to minimise the drug's side effects. Electron microscopy studies have shown that the AmB-CS aggregates are disks of ~115nm diameter, but their detailed architecture remains unknown. Such information, however, would be of significant benefit in the rational development of improved AmB formulations/delivery systems. It is the aim of the SANS studies proposed here to secure such information.